When I try to let the user sign in into Google+ via Google Game Services (using the GameHelper class), the login fails with this log-message:
05-16 17:34:44.620: ERROR/Volley(26441): [2299] il.a: Unexpected response code 400 for https://www.googleapis.com/games/v1whitelisted/applications?language=en_GB&platformType=ANDROID
05-16 17:34:44.620: ERROR/GameAgent(26441): Unable to retrieve 1P application xxxxxxxxxxxxxx.apps.googleusercontent.com from network
05-16 17:34:44.625: INFO/GameAgent(26441): {"code":400,"errors":[{"message":"Invalid applicationId with value xxxxxxxxxxxxxxxx.apps.googleusercontent.com","domain":"global","reason":"invalid"}]}
05-16 17:34:44.645: ERROR/CheckGameplayAcl(27604): Unable to load metadata for game
I've added all the metadata etc. correctly to my app and to the developer console, so it should work.