Google App Engine login fails with error 500 - google-app-engine

I have an appengine (Java) app with the ability to sign in via Google. For this I use
This has been working fine so far, and still works well locally (using mvn appengine:run) but on production it consistently throws a generic 500 while on /_ah/conflogin?state=~AJKiYcHHHXI45-... (the 5th URL of the login process, while already being logged in with Google) and I can find nothing relevant in the Logs Explorer at
I've since even updated to the latest but the problem remains.
Where should I look at to solve this issue?

To find the root cause of this issue, you can find the logs for this error will be helpful.
In this documentation there is a sample query that you could try to check for logs error with status 500.
resource.type="gae_app" AND
log_id("") AND
Alternatively you could also try running ‘gcloud app logs read’ as mentioned in this document to see if you get any logs.
The issue tracker mentioned by Rez in comment is marked as Fixed and after checking your issue I think it also relates to the same issue tracker. As it closed I suggest to get your issue resolved I recommend to raise new issue tracker by referencing the fixed one or else you may raise support ticket with google


Java IOException during API request to Stripe (APIConnectionException)

The specific action we are trying to performe is to create a charge request with Stripe:
Charge charge = Charge.create(params);
Using Stripe's Java implementation (version 5.35.1) we encounter a APIConnectionException when running the application on the deployed App Engine server. Interestingly, the issue does not occur using App Engine's local dev server.
We contacted Stripe and they said everything is fine on their side. They explained that "this error indicates that your server is not able to contact our API and that it ends up timing out waiting for an answer. Usually, this is due to something misconfigured on your server such as a DNS not redirecting to Stripe properly."
We were wondering if there are some configuration settings on App Engine which cause the problem. However, since there is no specific error message we cound not figure out what might cause the connection problem.
Similar problems which did not provide enough help to resolve this issue:
Thanks for your help!
The problem seems to have solved itself. It occured for a couple of days and since a few hours the exact same code is working fine. Just like in the problem is suddenly gone for some reason.

GAE: No longer able to update my Gaelyk project due to ClientLogin deprecation, what needs to change?

There are a couple of other questions that are closely related to this one, but neither of them have answers specific to a Gaelyk application.
When I try to use the appengineupdate Gradle command to update my Gaelyk application to the server, after entering my username and password, I get an error message: "Unable to update app: Bad authentication response: 404 Not Found".
It doesn't take much investigation to find that the error message is due to GAE deprecating their old ClientLogin authentication, and Google says to use new OAuth 2.0 authentication. However, how does one do this for a Gaelyk application? The documentation that exists is not of much help; I couldn't find any instructions specific to GAE or Gaelyk.
This turned out to be not very difficult at all.
In the build.gradle file, update the gaeVersion to the latest version. As of July 2016, it is:
def gaeVersion = '1.9.38'
Then, when you do the update, a Google page will open up, asking you to log in, and then it will give you a code to copy.
The update will wait for you to paste in the code, then the update should complete successfully.

Invalid and/or missing SSL certificate when using Google App Engine

UPDATE: Please, if anyone can help: Google is waiting for inputs and examples of this problem on their bug tracking tool. If you have reproducible steps for this issue, please share them on:
I'm trying to fetch data from the StackExchange API using a Google App Engine backend. As you may know, some of StackExchange's APIs are site-specific, requiring developers to run queries against every site the user is registered in.
So, here's my backend code for fetching timeline data from these sites. The feed_info_site variable holds the StackExchange site name (such as 'security', 'serverfault', etc.).
data = json.loads(urllib.urlopen("%sme/timeline?%s" %
(self.API_BASE_URL, urllib.urlencode({"pagesize": 100,
"fromdate": se_since_timestamp, "filter": "!9WWBR
(nmw", "site": feed_info_site, "access_token":
decrypt(self.API_ACCESS_TOKEN_SECRET, self.access_token), "key":
for item in data['items']:
... # code for parsing timeline items
When running this query on all sites except Stack Overflow, everything works OK. What's weird is, when the feed_info_site variable is set to 'stackoverflow', I get the following error from Google App Engine:
HTTPException: Invalid and/or missing SSL certificate for URL:
Of course, if I run the same query in Safari, I get the JSON results I'm expecting from the API. So the problem really lies in Google's URLfetch service. I found several topics here on Stack Overflow related to similar HTTPS/SSL exceptions, but no accepted answer solved my problems. I tried removing cacerts.txt files. I also tried making the call with validate_certificate=False, with no success.
I think the problem is not strictly related to HTTPS/SSL. If so, how would you explain that changing a single API parameter would make the request to fail?
Wait for the next update to the app engine (scheduled one soon) then update.
Replace with another service ( is a good service hosted by Mozilla what could be used)
Make sure cacerts.txt doesnt exist (looks like you have sorted but just in-case :-) )
Attempt again
Good luck!
I was facing the same error, google has updated the app engine now, error resolved, please check the updated docs.

Problems using Twitter4j on GAE throws 401 just after deploy

Well, I'm having a weird error here:
I'm developing one GAE app to read some Twitter Data, and after read a lot of docs, I have it working on my test server (Running on my pc) but after deploy and test on the real (my appspot domain) it shows this message:
401:Authentication credentials ( were missing or >incorrect. Ensure that you have set valid consumer key/secret, access token/secret, and the >system clock is in sync.
message - Could not authenticate you
code - 32
I've tried to recreate my OAuthAppToken and OAuthAppTokenSecret keys, even changing the permissions to "Write, Read and Direct Messages" and even assingning one Callback URL but nothing seems to work...
I've tried using OR using setOAuthConsumer(TW_CONSUMER_KEY, TW_CONSUMER_SECRET) OR a ConfigurationBuilder whith the correct constants and I'm experimenting the same Issue.
I'm working with AppEngine 1.8.3 and Twitter4j 3.0.4
Iv'e been writing on log and the Twitter object seems to be well created... I dont understand why is working on my PC but not on the real app.
On some other post someone says that could be because it needs to use Sync clock.. but he doesn't explains where to change that property...
Did someone had a clue?
Ok, the problem was me (and Twitter.... well..... I really think it was Twitter problem for being so dark on his api messages)...
On testing server I was looking for an existing account and on the cloud I was looking for an inexistent one. So, It was my mistake. But seriously, what about Twitter saying: "Access Forbidden"? That doesn't have any sense...

Google App Engine + Jersey + IntelliJ Idea

Okay so I'm having some annoying issue here. I am clearly missing something, and already been frustrating myself with this for the last 4-5 hours.
I cannot seem to be able to create a simple GAE+Jersey up and running with IntelliJ.
The frustrating part is that I do not get any errors, just that the REST service is not present after deployment.
I've tried out a few basic stuff, basically everything you can find on Google (and here).
After some frustration I've downloaded this project:
Just cause this will list out the available servers, plus the deeper logging level.
Now here's the output of the AppEngine startup:
So my problem: The AppEngine is up and running. If I create a basic servlet everyting works fine. However, I cannot get Jersey to work. In every form I could try it always throws an
Problem accessing /jerseyguicesample. Reason:
Powered by Jetty://
Any ideas, what I could be missing here?
Here's an image of the IDE and the artifact settings:
Thanks, :D
This example has REST handlers mapped to /rest/test, /rest/players/{name}/xml, /rest/players/{name}/json and /rest/hello.
What (and where) did you map /jerseyguicesample to?