Custom Domain Service Fails but Authentication Works (Silverlight Biz App Template) - silverlight

Question

I'm hosting a Silverlight Business Application Template derived application on an IIS Server. I'm using the built-in Forms Authentication which is working perfectly.
Unfortunately, I've added an additional service which has peculiar behavior. If I remote into the server and use the site everything works as expected. If I connect to the site from another PC, Authentication still works but my custom Domain Service is failing with the following error:
IE Throws this Error Message:
System.ServiceModel.DomainServices.Client.DomainOperationException:
Load operation failed for query
'Get___'. Exception of type
'System.ServiceModel.DomainServices.Client.DomainOperationException'
was thrown.
I tried debugging the process and get a little more information:
System.ServiceModel.DomainServices.Client.DomainOperationException:
Load operation failed for query
'Get___'. The remote server returned
an error:NotFound. --->
System.ServiceModel.CommunicationException:
...
My clientaccesspolicy and crossdomain policies are in both wwwroot and the root of the website and are the following:
<?xml version="1.0" encoding="utf-8" ?>
<access-policy>
<cross-domain-access>
<policy>
<allow-from http-request-headers="*">
<domain uri="*" />
<domain uri="http://*" />
<domain uri="https://*" />
</allow-from>
<grant-to>
<resource path="/" include-subpaths="true" />
</grant-to>
</policy>
</cross-domain-access>
</access-policy>
The Domain Service that's failing is using an ADO.NET Entity Model. The entities of which are in the same the aspnetdb database that is used for authentication and I've granted file permissions for the IIS User (and Administrator, I got desperate) for the App_Data folder which contains the db.
Again, all services work if connecting locally on the server. Only the Auth/Registration services works when connecting remotely.
I've searched for two days and tried every solution I can find but can't seem to get it working. Any advice or direction would be greatly appreciated.

Answer 1

Although this is pretty late for your project but it might help somebody else. Sounds like you are having problem with authenticating to the underlying database. You may want to look into what sort of impersonations are happening at database level.
I had a similar problem, and it turned out that I was trying to access the database as Sliverlight client pc account which never existed in authorized accounts (although my authentication was working perfectly just like in your case). Changing the Application Pool Identity fixed it for me (I was using Network Service account on a PC joined to a domain which uses Computer$ account to login on your behalf)
When you run into CommunicationException, you really want to look at InnerException which will tell what is the real issue.
If there's nothing then you'll need to debug on server side (step through service) to see what is throwing the exception.
CommunicationException occurs if an Exception is thrown on WCF server side and not wrapped into a fault causing the channel to become faulted (in my limited experience at least).
Hope this helps somebody.

Answer 2

WCF Tracing didn't help me! It gives an Empty message.
Finally,
FOR MY CASE,
I removed [RequiresAuthentication] like attributes from methods
I removed [RequiresAuthentication] from Domain Service Class (check all partials)
If it works on local but not on server it must be a configuration problem. In my case I used membership.ResetPassword() function which is disabled in web.config as enablePasswordReset=false.
Beside this some people says some methods just invoke-able in asp.net.compatibility mode.
Hope helps someone else.