SQL Server 2012 not able to connect to named instance remotely with ssms - sql-server

I'm running SQL Server 2012 on a Microsoft Windows Server 2012 R2. I am running a named instance called PP. The server authentication is set to "SQL Server and Windows Authentication mode".
When I am logged into the server via Remote Desktop I can log in to the named instance via SSMS just fine using a using a SQL Server username and password. When I try to log into the named instance remotely using the same username and password I get an error as described in this screenshot (my reputation isn't high enough to paste the screenshot directly in my post, please follow the link):
Here are the things I have checked so far:
I can ping the IP Address of the remote server from my local computer and get successful responses.
I have configured the instance of SQL Server to accept remote connections as described in this article.
In SQL Server Configuration Manager on the remote server under the protocols for my named instance I have enabled "Shared Memory", "Named Pipes" and "TCP/IP".
Under "TCP/IP" properties on the remote server in SQL Server Configuration Manager in the "IP Addresses" tab under the "IP2" section I have set the "TCP Dynamic Ports" value to blank. I have tried setting the "TCP Port" value to 1433 and then to 1434 (the difference between a regular instance and a named instance) and going through the rest of the steps below as shown in the screenshot here (these are the values specified in the article I linked to above)
Windows firewall is not running on the remote server, and from what I can see there is not another firewall running on the remote server either.
The SQL Server Browser service on the remote server has been stopped and restarted.
After I have made all of these changes and verified all of these settings the SQL Server service for the named instance on the remote server has been stopped and restarted.
After all of this I am still getting my original error when I try to connect to the named instance of SQL Server on my remote server from my local computer via SSMS. I've been searching high and low and cannot find any additional troubleshooting steps to diagnose this problem. Will someone please point me in the direction of the next steps I should take to fix this? Thanks in advance.


I logged off and then came back the next day to implement the suggestions in #Andrey Nikolov 's answer and for some reason I am able to connect remotely to the named instance now. The settings that ended up working for the "IP2" section of the "TCP/IP" configuration for the named instance are the "TCP Dynamic Ports" value is set to blank and the "TCP port" is set to 1433. I didn't make any other changes. The rest of the configuration is as I noted in my OP. I have sysadmin access to this server but I'm not the actual administrator so I guess it's possible that the actual administrator might have changed something else between when I logged off and then logged back on but I don't know what that might be. Thanks to #Andrey Nikolov for your input.
EDIT:
This issue came back in full force a few days later for no reason that I could determine. After a long search I found a very informative MS Doc that goes through the whole troubleshooting process for this in depth, hope this helps someone else confronted with this. Here's the link:
https://learn.microsoft.com/en-us/sql/database-engine/configure-windows/troubleshoot-connecting-to-the-sql-server-database-engine?view=sql-server-2017
It says it's for SQL Server 2017 but I was able to follow it to fix my SQL Server 2012 issue. For my situation it turns out that because I had 2 separate instances of MS SQL on my server the initial instance was using all of the default settings as described elsewhere and my instance I was trying to connect to was using a completely different port. Using this Doc I was able to find out what port my instance is using and specify that in the "Server name" box of SSMS when I tried to connect. Now it works like a charm.


I think your named instance TCP/IP isn't configured properly. In case you connect locally it does not connect using TCP/IP, but using shared memory. You set your instance to listen on port 1434, but this port is used by SQL Browser service and most likely the SQL Server engine service can't open the port (you can confirm that by finding the error in the logs). To make it work you should set IP2 -> TCP Dynamic Ports to be 0 and clear IP2 -> TCP Port. Configured like this, your named instance will use dynamic ports. If you want to configure it to use specific port, replace 1434 in IP2 -> TCP Port with available port number.

Related

SQL Server connection string windows 7 and windows 10 - Named Pipes Provider, error 40 [duplicate]

I can't seem to connect to my database from a site. I get this error:
Named Pipes Provider, error: 40 - Could not open a connection to SQL Server
I tried using the local IP address to connect as well as a public one. I've tried:
Yes, the site can communicate with the server
Named pipes/TCP is enabled.
Remote connections are allowed.
Windows Firewall is off
Created an exception for port 1433 in Windows Firewall.
Enabled everything in SQL Server Configuration Manager.
What else can I do here?

Solving this problem is very easy:
Go to control panel.
search for services.
Open Local services window from your search results
Restart your MSSQLSERVER service.
Screenshot of the steps:

And the simplest solution - check if your slash is back...
I spent about an hour trying to figure out what's wrong with SERVER/INSTANCENAME when everything is configured correctly, named pipes, user access rights... and suddenly it struck me, it's not a slash, it's a backslash (\).
The horror, the shame...

It's a three step process really after installing SQL Server:
Enable Named Pipes
SQL Config Manager --> SQL Server Network Consif --> Protocols --> Named Pipes --> Right-click --> Restart
Restart the server
SQL Config Manager --> SQL Server Services --> SQL Server (SQLEXPRESS) --> Right-click --> Restart
Use proper server and instance names (both are needed!)
Typically this would be .\SQLEXPRESS, for example see the screenshot from QueryExpress connection dialog.
There you have it.

I had just installed SQL SERVER 2012 developer. When I was creating my first SSIS package, I received this pipes error when I was trying to create a data connection task in SQL Server 2012 Data Tools in the Connection Manager box. I resolved with the help of the post above.
If choose a named instance and you call your named instance SSQDatabase1 and your pc's name is PCX1. You must enter PCX1\SSQDatabase1 not just SSQDatabase1
or you will receive the named pipes error.

A thread on MSDN Social, Re: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server, has a pretty decent list of possible issues that are related to your error. You may want to see if any of them could be what you're experiencing.
Incorrect connection string, such as using SqlExpress
Named Pipes(NP) was not enabled on the SQL instance
Remote connection was not enabled
Server not started, or point to not a real server in your connection string
Other reasons such as incorrect security context
try basic connectivity tests between the two machines you are working on

i Just enabled TCP/IP,VIA,Named Pipes in Sql Server Configuration manager , My problem got solved refer this for more info Resolving Named Pipes Error 40

Use SERVER\\ INSTANCE NAME .Using double backslash in my project solved my problem.

Thanks to Damian...
TCP/IP
Named Pipes
... both enabled
Web Config....(for localhost)
<add name="FooData" connectionString="Data Source=localhost\InstanceName;Initial Catalog=DatabaseName;Integrated Security=True;" providerName="System.Data.SqlClient" />

Did have the same problem. Spent like 6 hours when had to migrate some servers.
Tried all suggestions available on this topic and others.
Solution was as simple as server restart!

Very simple solution
use (local)\InstanceName
that's it. it worked for me.

TL;DR; Your SQL Server instance is using dynamic ports which is not working. Force SQL Server to use static port # 1433.
Complete Details: First of all this problem is more likely if you've a mix of default and named instance or named instances only(which was my case).
Key concept: Each instance of Microsoft SQL Server installed on a computer uses a different port to listen for incoming connection requests. Default instance of SQL Server uses port # 1433. As you install named instances then they will start using dynamic ports which is decided at the time of start-up of Windows service corresponding to named SQL Server instance.
My code was failing (with error code 40) to connect to the only named SQL Server instance that I had on my VM. You can try below possible solutions:
Solution # 1: Client code trying to connect to SQL Server instance takes help from SQL Server browser service to figure out port number at which your named instance is listening for incoming connections. Make sure SQL browser service is running on your computer.
Solution # 2: Check the port # (in yellow color) your named SQL Server instance is using from SQL Server configuration manager as shown in the snapshot below:
Use that port number explicitly in your connection string or with sqlcmd shown below:
sqlcmd -s mymachinename,11380 -i deleteDB.sql -o SQLDelete.txt
Solution # 3: Force your named instance to use port # 1433 which is used by default instance. Remember this will work only if you don't have any default SQL Server instance on your computer as the default SQL Server instance would be using using port # 1433 already. Same port number can't be uses by two different Windows services.
Mark TCP Dynamic ports field to blank and TCP Port field to 1433.
Change the port number in your connection string as shown below:
sqlcmd -s mymachinename\instanceName -i deleteDB.sql -o SQLDelete.txt
OR
sqlcmd -s mymachinename,1433 -i deleteDB.sql -o SQLDelete.txt
Note: Every change in TCP/IP settings requires corresponding Windows service restart.
Interestingly enough after resolving the error when I went back to dynamic port setting to reproduce the same error then it didn't happen. Not sure why.
Please read below interesting threads to know more about dynamic ports of SQL Server:
How to configure SQL Server Port on multiple instances?
When is a Dynamic Port “dynamic”?
When to use a TCP dynamic port and when TCP Port?
I got leads to solution of my problem from this blog.

in my case, i had a standalone server, i changed the sql server port default port 1433 in configuration manager to some number and restarted the sql serve service to take effect,i was able to connect to the sql server through management studio if i login to the server. but i was not able to connect from my local machine through sql server, i was getting the error:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and
that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 5)
I checked and verified all the below
-Named pipes/TCP is enabled.
-Remote connections are allowed.
-Windows Firewall is off
-Created an exception for portin Windows Firewall( this was not necessary in my case as the server is in same subnet network).
-Enabled everything in SQL Server Configuration Manager.
then i chnaged back the port number to default 1433 and restarted the sql server service, and the issue got resolved and i am able to connect the sql server from my local management studio.

I had the same problem. I use the MSSQL Server Management Studio 2017 and solved this problem using these steps:
Check for working fine SQL Server Services services or not.
Also check for working in good condition SQL Server (MSSQLSERVER).
Also check for working fine SQL Server Browser.
Restart SQL Server (MSSQLSERVER)
and fixed it.

You will find most likely your DB name is not correct, you will see the server name in VS like "DESKTOP-0I14BKI" but if you open up SSMS you will see DESKTOP-0I14BKI\SQLBLAHBLAH , simply add "\SQLBLAHBLAH" (instance name) to your "server name" in VS connection properties.
You will see:
To Fix:

Try the following steps:
Open Services window (open "run box" and type services.msc).
Looking for SQL services (with SQL prefix).
Start them (if cannot start. Goto step 4).
Right_click to each service -> Properties -> Change to tab "Log on"-> choise log on as "Local ..." -> 0K. Then start SQL services again.
Try Open SQL and connect database.

In my case,
I opened SQL Server Management Studio and searched for SQLEXPRESS in my Database engine.
It had two instances and I selected the correct one.

If you are working with Asp.net core and using appsettings.json than write server as localhost and after write sql instance name for enabled named pipe like this
"ConnectionString": {
"dewDB": "server=localhost\\dewelopersql;database=dewdb;User ID=sa;password=XXXXX",
},

After following all the steps mentioned here, if it still does not connect, try adding the DNS with the IP address in the hosts file in the etc folder. Adding an IP address instead of DNS name in the connection string should be a temporary solution to check if the connection actually works.

I tried using the local IP address to connect as well as a public one.
I've tried:
Yes, the site can communicate with the server Named pipes/TCP is
enabled. Remote connections are allowed. Windows Firewall is off
Created an exception for port 1433 in Windows Firewall. Enabled
everything in SQL Server Configuration Manager.
i ensured and did the above as well and I just want to share that the DOUBLE BACKSLASH
oBuilder.DataSource = "SPECIFICPCNAME\SQLEXPRESS";
Using a SINGLE BACKSLASH resulted into a build error i.e.: Error 1 Unrecognized escape sequence
I hope this helps the next guy - I've sacrificed dinner, midnight snack and NBA highlights time solving this (shame)
Thanks to [Tamizh venthan]
^_^

Enable TCP/Ip , Piped Protocol by going to Computer Management ->SQL and Services, ensure the Service is On. Enbale the port on the Firewall. Try to login through Command Prompt -> as Admin; last the User Name
should be (local)\SQLEXPRESS. Hope this helps.

Open SQL Server Configuration Manager
Select SQL Server Services from right.
Find your server from right and go to its properties (with right click)
Change log on method to Local System.

I had the same problem and solved the problem by disabling my firewall(ESET).
The first step to solve this problem should be to try pinging your own computer from another computer. If you have firewall on, you may not be able to ping yourself. I tried pinging my own pc, then ping was failed(didnt get response from the server)

I was trying to add a new connection in VS2015. None of the suggestions here worked. Suspecting some sort of a bug in the wizard, especially since SSMS was able to connect just fine, I decided to try and trick it. It worked!
Instead of adding the connection, use "Create new SQL Server Database". Enter your server name and a random name for the new DB, e.g. "test".
Assuming this succeeds, open Server Explorer in VS, locate the connection in Data Connections, right-click it and select Modify Connection.
Change "test" (from step 1) to the name of the existing database you want to connect to. Click "Test Connection". This time it should work!
Delete the temporary database you created in step 1.

I have one more solution, I think.
I recently had changed my computer name so, after I couldn't connect still after trying all above methods.
I changed the Server name..
Server name => (browse for more) => under database engine, a new server was found same as computers new name.
This worked, and life is good again.

I struggled for ages on this one before I realized my error - I had used commas instead of semicolons in the connect string

I had this issue but none of the suggestions above fixed it.
I was seeing this issue when I deployed my website to IIS. The fix was to go into advanced settings against the default app pool and change the identity property from the default to Administrator.

For me it was a Firewall issue.
First you have to add the port (such as 1444 and maybe 1434) but also
C:\Program Files (x86)\Microsoft SQL Server\90\Shared\sqlbrowser.exe
and
%ProgramFiles%\Microsoft SQL Server\MSSQL12.SQLEXPRESS\MSSQL\Binn\SQLAGENT.EXE
The second time I got this issue is when I came back to the firewall, the paths were not correct and I needed to update form 12 to 13! Simply clicking on browse in the Programs and Services tab helped to realise this.
Finally, try running the command
EXEC xp_readerrorlog 0,1,"could not register the Service Principal Name",Null
For me, it returned the error reason

I tried pretty much everything on this page but I had some underlying issues which were actually what needed to be resolved. I was unable to do certain things like open SQL Server Configuration Manager, which ended up being corrupt/missing WMI provider files.
There are lots of tedious ways to resolve this issues according to what I've read, but the tool from tweaking.com was able to remove and replace/repair my WMI (Windows Management Instrumentation) Provider files.
I used to do computer repair and overall the tweaking.com tool really impressed me, and it was suggested from one of the WMI error forum pages I went to.
After I fixed this issue I was able to connect to my SQL db, both locally and remotely.
Hope this helps someone.

open port number 1433 on your server for sql remote connection

If you tried restarting the MSSQLSERVER service, and it did not work, this might be a solution:
If you are using SQLExpress, your server name should be as the following ComputerName\SQLExpress. However, for SQLDeveloper, you do not have to right SQLDeveloper after your ComputerName.

ASP.NET MVC & SQL Server [duplicate]

I can't seem to connect to my database from a site. I get this error:
Named Pipes Provider, error: 40 - Could not open a connection to SQL Server
I tried using the local IP address to connect as well as a public one. I've tried:
Yes, the site can communicate with the server
Named pipes/TCP is enabled.
Remote connections are allowed.
Windows Firewall is off
Created an exception for port 1433 in Windows Firewall.
Enabled everything in SQL Server Configuration Manager.
What else can I do here?

Solving this problem is very easy:
Go to control panel.
search for services.
Open Local services window from your search results
Restart your MSSQLSERVER service.
Screenshot of the steps:

And the simplest solution - check if your slash is back...
I spent about an hour trying to figure out what's wrong with SERVER/INSTANCENAME when everything is configured correctly, named pipes, user access rights... and suddenly it struck me, it's not a slash, it's a backslash (\).
The horror, the shame...

It's a three step process really after installing SQL Server:
Enable Named Pipes
SQL Config Manager --> SQL Server Network Consif --> Protocols --> Named Pipes --> Right-click --> Restart
Restart the server
SQL Config Manager --> SQL Server Services --> SQL Server (SQLEXPRESS) --> Right-click --> Restart
Use proper server and instance names (both are needed!)
Typically this would be .\SQLEXPRESS, for example see the screenshot from QueryExpress connection dialog.
There you have it.

I had just installed SQL SERVER 2012 developer. When I was creating my first SSIS package, I received this pipes error when I was trying to create a data connection task in SQL Server 2012 Data Tools in the Connection Manager box. I resolved with the help of the post above.
If choose a named instance and you call your named instance SSQDatabase1 and your pc's name is PCX1. You must enter PCX1\SSQDatabase1 not just SSQDatabase1
or you will receive the named pipes error.

A thread on MSDN Social, Re: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server, has a pretty decent list of possible issues that are related to your error. You may want to see if any of them could be what you're experiencing.
Incorrect connection string, such as using SqlExpress
Named Pipes(NP) was not enabled on the SQL instance
Remote connection was not enabled
Server not started, or point to not a real server in your connection string
Other reasons such as incorrect security context
try basic connectivity tests between the two machines you are working on

i Just enabled TCP/IP,VIA,Named Pipes in Sql Server Configuration manager , My problem got solved refer this for more info Resolving Named Pipes Error 40

Use SERVER\\ INSTANCE NAME .Using double backslash in my project solved my problem.

Thanks to Damian...
TCP/IP
Named Pipes
... both enabled
Web Config....(for localhost)
<add name="FooData" connectionString="Data Source=localhost\InstanceName;Initial Catalog=DatabaseName;Integrated Security=True;" providerName="System.Data.SqlClient" />

Did have the same problem. Spent like 6 hours when had to migrate some servers.
Tried all suggestions available on this topic and others.
Solution was as simple as server restart!

Very simple solution
use (local)\InstanceName
that's it. it worked for me.

TL;DR; Your SQL Server instance is using dynamic ports which is not working. Force SQL Server to use static port # 1433.
Complete Details: First of all this problem is more likely if you've a mix of default and named instance or named instances only(which was my case).
Key concept: Each instance of Microsoft SQL Server installed on a computer uses a different port to listen for incoming connection requests. Default instance of SQL Server uses port # 1433. As you install named instances then they will start using dynamic ports which is decided at the time of start-up of Windows service corresponding to named SQL Server instance.
My code was failing (with error code 40) to connect to the only named SQL Server instance that I had on my VM. You can try below possible solutions:
Solution # 1: Client code trying to connect to SQL Server instance takes help from SQL Server browser service to figure out port number at which your named instance is listening for incoming connections. Make sure SQL browser service is running on your computer.
Solution # 2: Check the port # (in yellow color) your named SQL Server instance is using from SQL Server configuration manager as shown in the snapshot below:
Use that port number explicitly in your connection string or with sqlcmd shown below:
sqlcmd -s mymachinename,11380 -i deleteDB.sql -o SQLDelete.txt
Solution # 3: Force your named instance to use port # 1433 which is used by default instance. Remember this will work only if you don't have any default SQL Server instance on your computer as the default SQL Server instance would be using using port # 1433 already. Same port number can't be uses by two different Windows services.
Mark TCP Dynamic ports field to blank and TCP Port field to 1433.
Change the port number in your connection string as shown below:
sqlcmd -s mymachinename\instanceName -i deleteDB.sql -o SQLDelete.txt
OR
sqlcmd -s mymachinename,1433 -i deleteDB.sql -o SQLDelete.txt
Note: Every change in TCP/IP settings requires corresponding Windows service restart.
Interestingly enough after resolving the error when I went back to dynamic port setting to reproduce the same error then it didn't happen. Not sure why.
Please read below interesting threads to know more about dynamic ports of SQL Server:
How to configure SQL Server Port on multiple instances?
When is a Dynamic Port “dynamic”?
When to use a TCP dynamic port and when TCP Port?
I got leads to solution of my problem from this blog.

in my case, i had a standalone server, i changed the sql server port default port 1433 in configuration manager to some number and restarted the sql serve service to take effect,i was able to connect to the sql server through management studio if i login to the server. but i was not able to connect from my local machine through sql server, i was getting the error:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and
that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 5)
I checked and verified all the below
-Named pipes/TCP is enabled.
-Remote connections are allowed.
-Windows Firewall is off
-Created an exception for portin Windows Firewall( this was not necessary in my case as the server is in same subnet network).
-Enabled everything in SQL Server Configuration Manager.
then i chnaged back the port number to default 1433 and restarted the sql server service, and the issue got resolved and i am able to connect the sql server from my local management studio.

I had the same problem. I use the MSSQL Server Management Studio 2017 and solved this problem using these steps:
Check for working fine SQL Server Services services or not.
Also check for working in good condition SQL Server (MSSQLSERVER).
Also check for working fine SQL Server Browser.
Restart SQL Server (MSSQLSERVER)
and fixed it.

You will find most likely your DB name is not correct, you will see the server name in VS like "DESKTOP-0I14BKI" but if you open up SSMS you will see DESKTOP-0I14BKI\SQLBLAHBLAH , simply add "\SQLBLAHBLAH" (instance name) to your "server name" in VS connection properties.
You will see:
To Fix:

Try the following steps:
Open Services window (open "run box" and type services.msc).
Looking for SQL services (with SQL prefix).
Start them (if cannot start. Goto step 4).
Right_click to each service -> Properties -> Change to tab "Log on"-> choise log on as "Local ..." -> 0K. Then start SQL services again.
Try Open SQL and connect database.

In my case,
I opened SQL Server Management Studio and searched for SQLEXPRESS in my Database engine.
It had two instances and I selected the correct one.

If you are working with Asp.net core and using appsettings.json than write server as localhost and after write sql instance name for enabled named pipe like this
"ConnectionString": {
"dewDB": "server=localhost\\dewelopersql;database=dewdb;User ID=sa;password=XXXXX",
},

After following all the steps mentioned here, if it still does not connect, try adding the DNS with the IP address in the hosts file in the etc folder. Adding an IP address instead of DNS name in the connection string should be a temporary solution to check if the connection actually works.

I tried using the local IP address to connect as well as a public one.
I've tried:
Yes, the site can communicate with the server Named pipes/TCP is
enabled. Remote connections are allowed. Windows Firewall is off
Created an exception for port 1433 in Windows Firewall. Enabled
everything in SQL Server Configuration Manager.
i ensured and did the above as well and I just want to share that the DOUBLE BACKSLASH
oBuilder.DataSource = "SPECIFICPCNAME\SQLEXPRESS";
Using a SINGLE BACKSLASH resulted into a build error i.e.: Error 1 Unrecognized escape sequence
I hope this helps the next guy - I've sacrificed dinner, midnight snack and NBA highlights time solving this (shame)
Thanks to [Tamizh venthan]
^_^

Enable TCP/Ip , Piped Protocol by going to Computer Management ->SQL and Services, ensure the Service is On. Enbale the port on the Firewall. Try to login through Command Prompt -> as Admin; last the User Name
should be (local)\SQLEXPRESS. Hope this helps.

Open SQL Server Configuration Manager
Select SQL Server Services from right.
Find your server from right and go to its properties (with right click)
Change log on method to Local System.

I had the same problem and solved the problem by disabling my firewall(ESET).
The first step to solve this problem should be to try pinging your own computer from another computer. If you have firewall on, you may not be able to ping yourself. I tried pinging my own pc, then ping was failed(didnt get response from the server)

I was trying to add a new connection in VS2015. None of the suggestions here worked. Suspecting some sort of a bug in the wizard, especially since SSMS was able to connect just fine, I decided to try and trick it. It worked!
Instead of adding the connection, use "Create new SQL Server Database". Enter your server name and a random name for the new DB, e.g. "test".
Assuming this succeeds, open Server Explorer in VS, locate the connection in Data Connections, right-click it and select Modify Connection.
Change "test" (from step 1) to the name of the existing database you want to connect to. Click "Test Connection". This time it should work!
Delete the temporary database you created in step 1.

I have one more solution, I think.
I recently had changed my computer name so, after I couldn't connect still after trying all above methods.
I changed the Server name..
Server name => (browse for more) => under database engine, a new server was found same as computers new name.
This worked, and life is good again.

I struggled for ages on this one before I realized my error - I had used commas instead of semicolons in the connect string

I had this issue but none of the suggestions above fixed it.
I was seeing this issue when I deployed my website to IIS. The fix was to go into advanced settings against the default app pool and change the identity property from the default to Administrator.

For me it was a Firewall issue.
First you have to add the port (such as 1444 and maybe 1434) but also
C:\Program Files (x86)\Microsoft SQL Server\90\Shared\sqlbrowser.exe
and
%ProgramFiles%\Microsoft SQL Server\MSSQL12.SQLEXPRESS\MSSQL\Binn\SQLAGENT.EXE
The second time I got this issue is when I came back to the firewall, the paths were not correct and I needed to update form 12 to 13! Simply clicking on browse in the Programs and Services tab helped to realise this.
Finally, try running the command
EXEC xp_readerrorlog 0,1,"could not register the Service Principal Name",Null
For me, it returned the error reason

I tried pretty much everything on this page but I had some underlying issues which were actually what needed to be resolved. I was unable to do certain things like open SQL Server Configuration Manager, which ended up being corrupt/missing WMI provider files.
There are lots of tedious ways to resolve this issues according to what I've read, but the tool from tweaking.com was able to remove and replace/repair my WMI (Windows Management Instrumentation) Provider files.
I used to do computer repair and overall the tweaking.com tool really impressed me, and it was suggested from one of the WMI error forum pages I went to.
After I fixed this issue I was able to connect to my SQL db, both locally and remotely.
Hope this helps someone.

open port number 1433 on your server for sql remote connection

If you tried restarting the MSSQLSERVER service, and it did not work, this might be a solution:
If you are using SQLExpress, your server name should be as the following ComputerName\SQLExpress. However, for SQLDeveloper, you do not have to right SQLDeveloper after your ComputerName.

Cannot connect to SQL Server named instance

I cannot connect to a named instance of SQL Server. I am trying to connect to domain\named_instance but this happens to all servers I try to connect to apart from localhost
The error that I cam getting looks like this:
So far I have tried:
Enabling remote connections in SQL Server
Enabling TCP/IP in the SQL Server Configuration Manager
Changing all the TCP ports in SQL Server Configuration Manager to 1433
I also tried running the command below where the number is the Process ID of the SQL Server Service:
netstat -ano | find /i “7608”
My result was as follows:
As suggested by this website.
However I do not get the ESTABLISHED return only the 2 LISTENING ones.
My IP2 IP address is set to: 192.168.2.176not 100% sure if this is right or not.
I cannot (due to security issues with my hosting company) get the IP of the server. Any and all suggestions are welcome!
I am in dire straits, and really need help!
I am using SQL Server 2008

Since you are stating you are trying to use named pipes (can be seen in the screenshots) I think you errornously trying to use TCP configuration to do this.
You need to need to enabled SQL to listen named pipes. How to do - see here.

There are multiple types of error "Cannot connect to 'Server Name'".
These error are differentiated on the basis of Error Additional Information.
One of the Solution for above error is
Connect the server using Windows Authentication.
Right Click on the Server(i.e. first option) in Object Explorer. Then go to Properties.
Go to Security then select Server Authentication as "SQL Server and Windows Authentication Mode"
Again Right Click on the Server(i.e. first option) in Object Explorer. Then select restart.
Then try again login using SQL Authentication

How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'?

I can't seem to connect to my database from a site. I get this error:
Named Pipes Provider, error: 40 - Could not open a connection to SQL Server
I tried using the local IP address to connect as well as a public one. I've tried:
Yes, the site can communicate with the server
Named pipes/TCP is enabled.
Remote connections are allowed.
Windows Firewall is off
Created an exception for port 1433 in Windows Firewall.
Enabled everything in SQL Server Configuration Manager.
What else can I do here?

Solving this problem is very easy:
Go to control panel.
search for services.
Open Local services window from your search results
Restart your MSSQLSERVER service.
Screenshot of the steps:

And the simplest solution - check if your slash is back...
I spent about an hour trying to figure out what's wrong with SERVER/INSTANCENAME when everything is configured correctly, named pipes, user access rights... and suddenly it struck me, it's not a slash, it's a backslash (\).
The horror, the shame...

It's a three step process really after installing SQL Server:
Enable Named Pipes
SQL Config Manager --> SQL Server Network Consif --> Protocols --> Named Pipes --> Right-click --> Restart
Restart the server
SQL Config Manager --> SQL Server Services --> SQL Server (SQLEXPRESS) --> Right-click --> Restart
Use proper server and instance names (both are needed!)
Typically this would be .\SQLEXPRESS, for example see the screenshot from QueryExpress connection dialog.
There you have it.

I had just installed SQL SERVER 2012 developer. When I was creating my first SSIS package, I received this pipes error when I was trying to create a data connection task in SQL Server 2012 Data Tools in the Connection Manager box. I resolved with the help of the post above.
If choose a named instance and you call your named instance SSQDatabase1 and your pc's name is PCX1. You must enter PCX1\SSQDatabase1 not just SSQDatabase1
or you will receive the named pipes error.

A thread on MSDN Social, Re: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server, has a pretty decent list of possible issues that are related to your error. You may want to see if any of them could be what you're experiencing.
Incorrect connection string, such as using SqlExpress
Named Pipes(NP) was not enabled on the SQL instance
Remote connection was not enabled
Server not started, or point to not a real server in your connection string
Other reasons such as incorrect security context
try basic connectivity tests between the two machines you are working on

i Just enabled TCP/IP,VIA,Named Pipes in Sql Server Configuration manager , My problem got solved refer this for more info Resolving Named Pipes Error 40

Use SERVER\\ INSTANCE NAME .Using double backslash in my project solved my problem.

Thanks to Damian...
TCP/IP
Named Pipes
... both enabled
Web Config....(for localhost)
<add name="FooData" connectionString="Data Source=localhost\InstanceName;Initial Catalog=DatabaseName;Integrated Security=True;" providerName="System.Data.SqlClient" />

Did have the same problem. Spent like 6 hours when had to migrate some servers.
Tried all suggestions available on this topic and others.
Solution was as simple as server restart!

Very simple solution
use (local)\InstanceName
that's it. it worked for me.

TL;DR; Your SQL Server instance is using dynamic ports which is not working. Force SQL Server to use static port # 1433.
Complete Details: First of all this problem is more likely if you've a mix of default and named instance or named instances only(which was my case).
Key concept: Each instance of Microsoft SQL Server installed on a computer uses a different port to listen for incoming connection requests. Default instance of SQL Server uses port # 1433. As you install named instances then they will start using dynamic ports which is decided at the time of start-up of Windows service corresponding to named SQL Server instance.
My code was failing (with error code 40) to connect to the only named SQL Server instance that I had on my VM. You can try below possible solutions:
Solution # 1: Client code trying to connect to SQL Server instance takes help from SQL Server browser service to figure out port number at which your named instance is listening for incoming connections. Make sure SQL browser service is running on your computer.
Solution # 2: Check the port # (in yellow color) your named SQL Server instance is using from SQL Server configuration manager as shown in the snapshot below:
Use that port number explicitly in your connection string or with sqlcmd shown below:
sqlcmd -s mymachinename,11380 -i deleteDB.sql -o SQLDelete.txt
Solution # 3: Force your named instance to use port # 1433 which is used by default instance. Remember this will work only if you don't have any default SQL Server instance on your computer as the default SQL Server instance would be using using port # 1433 already. Same port number can't be uses by two different Windows services.
Mark TCP Dynamic ports field to blank and TCP Port field to 1433.
Change the port number in your connection string as shown below:
sqlcmd -s mymachinename\instanceName -i deleteDB.sql -o SQLDelete.txt
OR
sqlcmd -s mymachinename,1433 -i deleteDB.sql -o SQLDelete.txt
Note: Every change in TCP/IP settings requires corresponding Windows service restart.
Interestingly enough after resolving the error when I went back to dynamic port setting to reproduce the same error then it didn't happen. Not sure why.
Please read below interesting threads to know more about dynamic ports of SQL Server:
How to configure SQL Server Port on multiple instances?
When is a Dynamic Port “dynamic”?
When to use a TCP dynamic port and when TCP Port?
I got leads to solution of my problem from this blog.

in my case, i had a standalone server, i changed the sql server port default port 1433 in configuration manager to some number and restarted the sql serve service to take effect,i was able to connect to the sql server through management studio if i login to the server. but i was not able to connect from my local machine through sql server, i was getting the error:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and
that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 5)
I checked and verified all the below
-Named pipes/TCP is enabled.
-Remote connections are allowed.
-Windows Firewall is off
-Created an exception for portin Windows Firewall( this was not necessary in my case as the server is in same subnet network).
-Enabled everything in SQL Server Configuration Manager.
then i chnaged back the port number to default 1433 and restarted the sql server service, and the issue got resolved and i am able to connect the sql server from my local management studio.

I had the same problem. I use the MSSQL Server Management Studio 2017 and solved this problem using these steps:
Check for working fine SQL Server Services services or not.
Also check for working in good condition SQL Server (MSSQLSERVER).
Also check for working fine SQL Server Browser.
Restart SQL Server (MSSQLSERVER)
and fixed it.

You will find most likely your DB name is not correct, you will see the server name in VS like "DESKTOP-0I14BKI" but if you open up SSMS you will see DESKTOP-0I14BKI\SQLBLAHBLAH , simply add "\SQLBLAHBLAH" (instance name) to your "server name" in VS connection properties.
You will see:
To Fix:

Try the following steps:
Open Services window (open "run box" and type services.msc).
Looking for SQL services (with SQL prefix).
Start them (if cannot start. Goto step 4).
Right_click to each service -> Properties -> Change to tab "Log on"-> choise log on as "Local ..." -> 0K. Then start SQL services again.
Try Open SQL and connect database.

In my case,
I opened SQL Server Management Studio and searched for SQLEXPRESS in my Database engine.
It had two instances and I selected the correct one.

If you are working with Asp.net core and using appsettings.json than write server as localhost and after write sql instance name for enabled named pipe like this
"ConnectionString": {
"dewDB": "server=localhost\\dewelopersql;database=dewdb;User ID=sa;password=XXXXX",
},

After following all the steps mentioned here, if it still does not connect, try adding the DNS with the IP address in the hosts file in the etc folder. Adding an IP address instead of DNS name in the connection string should be a temporary solution to check if the connection actually works.

I tried using the local IP address to connect as well as a public one.
I've tried:
Yes, the site can communicate with the server Named pipes/TCP is
enabled. Remote connections are allowed. Windows Firewall is off
Created an exception for port 1433 in Windows Firewall. Enabled
everything in SQL Server Configuration Manager.
i ensured and did the above as well and I just want to share that the DOUBLE BACKSLASH
oBuilder.DataSource = "SPECIFICPCNAME\SQLEXPRESS";
Using a SINGLE BACKSLASH resulted into a build error i.e.: Error 1 Unrecognized escape sequence
I hope this helps the next guy - I've sacrificed dinner, midnight snack and NBA highlights time solving this (shame)
Thanks to [Tamizh venthan]
^_^

Enable TCP/Ip , Piped Protocol by going to Computer Management ->SQL and Services, ensure the Service is On. Enbale the port on the Firewall. Try to login through Command Prompt -> as Admin; last the User Name
should be (local)\SQLEXPRESS. Hope this helps.

Open SQL Server Configuration Manager
Select SQL Server Services from right.
Find your server from right and go to its properties (with right click)
Change log on method to Local System.

I had the same problem and solved the problem by disabling my firewall(ESET).
The first step to solve this problem should be to try pinging your own computer from another computer. If you have firewall on, you may not be able to ping yourself. I tried pinging my own pc, then ping was failed(didnt get response from the server)

I was trying to add a new connection in VS2015. None of the suggestions here worked. Suspecting some sort of a bug in the wizard, especially since SSMS was able to connect just fine, I decided to try and trick it. It worked!
Instead of adding the connection, use "Create new SQL Server Database". Enter your server name and a random name for the new DB, e.g. "test".
Assuming this succeeds, open Server Explorer in VS, locate the connection in Data Connections, right-click it and select Modify Connection.
Change "test" (from step 1) to the name of the existing database you want to connect to. Click "Test Connection". This time it should work!
Delete the temporary database you created in step 1.

I have one more solution, I think.
I recently had changed my computer name so, after I couldn't connect still after trying all above methods.
I changed the Server name..
Server name => (browse for more) => under database engine, a new server was found same as computers new name.
This worked, and life is good again.

I struggled for ages on this one before I realized my error - I had used commas instead of semicolons in the connect string

I had this issue but none of the suggestions above fixed it.
I was seeing this issue when I deployed my website to IIS. The fix was to go into advanced settings against the default app pool and change the identity property from the default to Administrator.

For me it was a Firewall issue.
First you have to add the port (such as 1444 and maybe 1434) but also
C:\Program Files (x86)\Microsoft SQL Server\90\Shared\sqlbrowser.exe
and
%ProgramFiles%\Microsoft SQL Server\MSSQL12.SQLEXPRESS\MSSQL\Binn\SQLAGENT.EXE
The second time I got this issue is when I came back to the firewall, the paths were not correct and I needed to update form 12 to 13! Simply clicking on browse in the Programs and Services tab helped to realise this.
Finally, try running the command
EXEC xp_readerrorlog 0,1,"could not register the Service Principal Name",Null
For me, it returned the error reason

I tried pretty much everything on this page but I had some underlying issues which were actually what needed to be resolved. I was unable to do certain things like open SQL Server Configuration Manager, which ended up being corrupt/missing WMI provider files.
There are lots of tedious ways to resolve this issues according to what I've read, but the tool from tweaking.com was able to remove and replace/repair my WMI (Windows Management Instrumentation) Provider files.
I used to do computer repair and overall the tweaking.com tool really impressed me, and it was suggested from one of the WMI error forum pages I went to.
After I fixed this issue I was able to connect to my SQL db, both locally and remotely.
Hope this helps someone.

open port number 1433 on your server for sql remote connection

If you tried restarting the MSSQLSERVER service, and it did not work, this might be a solution:
If you are using SQLExpress, your server name should be as the following ComputerName\SQLExpress. However, for SQLDeveloper, you do not have to right SQLDeveloper after your ComputerName.

Unable to connect to SQL Server instance remotely

I’m trying to access the SQL Server instance on my VPS from SQL Server Management Studio on my local machine. It’s not working (the error I’m getting is:
A network-related or instance-specific error occurred while
establishing a connection to SQL Server. The server was not found or
was not accessible. Verify that the instance name is correct and that
SQL Server is configured to allow remote connections.
I think this is because I need to configure the database engine to allow remote connections (correct me if I’m wrong!). So I’ve found this step-by-step guide to help me do that: http://www.linglom.com/2009/03/28/enable-remote-connection-on-sql-server-2008-express/ I’ve got to point 10 in the guide and I am now stuck! I don’t have SQL Server Management Studio installed on my VPS. Anyway, this has left me with two options:
Install SSMS
Find another way to do point 10 onwards in the guide without having SSMS installed
I tried installing SSMS on my VPS using the Web Platform Installer but it keeps failing. I don’t know why it’s failing because it doesn’t seem to give a reason why. Does anyone know how I could allow remote connections a different way?
The version of SQL Server installed on my VPS is SQL Server 2008 R2 Express.
Update:
I have tried to disable the firewall on both my laptop and VPS to see if it is a firewall issue. This made no difference to the error message.
Another Update:
Having now been able to install SSMS (I installed directly from the website rather than using the WPI), I have been able to check that the server is configured to allow remote connections (I went to SSMS, connected to the SQL Server instance, right-clicked on the connection, clicked Properties, went to the Connections tab. "Allow remote connections to this server" is already ticked).
SOLUTION
Thanks to everyone for helping me get to this solution! I've finally managed to get it to work! I followed Filip De Vos's advice and opened the ports in the Firewall on my VPS and then I received a different error message. This led me to investigate further and I found that I was using the wrong credentials to login! So I've set a password for the sa user and I've managed to login using that! Thanks again!

To enable mixed authentication you can change the following registry key:
HKLM\Software\Microsoft\Microsoft SQL Server\MSSQL.1\MSSQLServer\LoginMode
Update the value to 2 and restart the Sql Server service to allow mixed authentication. Note that MSSQL.1 might need to be updated to reflect the number of the SQL Server Instance you are attempting to change.
A reason for connection errors can be a virus scanner installed on the server which blocks sqlserver.exe.
Another reason can be that the SQL Server Browser service is not running. When this service is not running you cannot connect on named instances (when they are using dynamic ports).
It is also possible that Sql Server is not setup to listen to TCP connections and only allows named pipes.
In the Start Menu, open Programs > Microsoft SQL Server 2008 >
Configuration Tools > SQL Server Surface Area Configuration
In the Surface Area Configuration utility, click the link "SQL Server
Configuration Manager"
Expand "SQL Server Network Configuration" and
select Protocols.
Enable TCP/IP. If you need Named Pipes, then you can
enable them here as well.
Last but not least, the Windows firewall needs to allow connections to SQL Server
Add an exception for sqlserver.exe when you use the "Dynamic Port" system.
Otherwise you can put exceptions for the SQL Server ports (default port 1433)
Also add an exception for the SQL Server Browser. (udp port 1434)
More information:
How to: Configure a Windows Firewall for Database Engine Access
Server Connectivity How-to Topics (Database Engine)
As a last note, SqlLocalDB only supports named pipes, so you can not connect to it over the network.

In addition to configuring the SQL Server Browser service in Services.msc to Automatic, and starting the service, I had to enable TCP/IP in: SQL Server Configuration Manager | SQL Server Network Configuration | Protocols for [INSTANCE NAME] | TCP/IP

Launch SQL Server Configuration Manager on your VPS.
Take a look at the SQL Server Network Configuration. Make sure that TCP/IP is enabled.
Next look at SQL Server Services. Make sure that SQL Server Browser is running.
Restart the service for your instance of SQL Server.

Open the SQL Server Configuration Manager....
2.Check wheather TCP and UDP are running or not....
3.If not running , Please enable them and also check the SQL Server Browser is running or not.If not running turn it on.....
Next you have to check which ports TCP and UDP is using. You have to open those ports from your windows firewall.....
5.Click here to see the steps to open a specific port in windows firewall....
Now SQL Server is ready to access over LAN.......
If you wan to access it remotely (over internet) , you have to do another job that is 'Port Forwarding'. You have open the ports TCP and UDP is using in SQL Server on your router. Now the configuration of routers are different. If you give me the details of your router (i. e name of the company and version ) , I can show you the steps how to forward a specific port.

I had the same issue where my firewall was configured properly, TCP/IP was enabled in SQL Server Configuration Manager but I still could not access my SQL database from outside the computer hosting it. I found the solution was SQL Server Browser was disabled by default in Services (and no option was available to enable it in SQL Server Configuration Manager).
I enabled it by Control Panel > Administrative Tools > Services then double click on SQL Server Browser. In the General tab set the startup type to Automatic using the drop down list. Then go back into SQL Server Configuration Manager and check that the SQL Server Browser is enabled. Hope this helps.

Disable the firewall and try to connect.
If that works, then enable the firewall and
Windows Defender Firewall -> Advanced Settings -> Inbound Rules(Right Click) -> New Rules -> Port -> Allow Port 1433 (Public and Private) -> Add
Do the same for Outbound Rules.
Then Try again.

I recently upgraded from SQL 2008 R2 to SQL 2012 and had a similar issue. The problem was the firewall, but more specifically the firewall rule for SQL SERVER. The custom rule was pointed to the prior version of SQL Server. Try this, open Windows Firewall>Advanced setting. Find the SQL Server Rule (it may have a custom name). Right-Click and go to properties, then Programs and Services Tab. If Programs-This program is selected, you should browse for the proper version of sqlserver.exe.

If you have more than one Instances... Then make sure the PORT Numbers of all Instances are Unique and no one's PORT Number is 1433 except Default One...

Open SQL Server Configuration Manager.
Click SQL Server Services, on the right side choose the server you've created during installation (by default its state is stopped), click once on it and a play button should appear on the toolbar. Click on this play button, wait til its state turns to "Running". Now you're good.
Open SQL Server Management Studio; switch the "Server Type" to "Database Engine" and "Authentication" to "SQL Server Authentication". The default login is "sa", and the password is the password that you chose on creating the server. Now you're good to work.

In my case the problem was caused by the inconsistency between computer names. In system settings my computer was named with some long name, but apparently the name used for some certain communications was trimmed.
I changed the name in the settings to a shorter one and it worked.

I had built both a console app and a UWP app and my console connected fine, but not my UWP. After hours of banging my head against the desk - if it's a intranet server hosting the SQL database you must enable "Private Networks (Client & Server)". It's under Package.appxmanifest and the Capabilities tab.Screenshot

Before download the last version and update your sql server to fix errors of TLS 1.2 on Sql Server 2012. For more information, check here.

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