Google play authentication failed after adding keystore

Ok, in order to log google play in my game i call

 Social.Active.localUser.Authenticate(authentication);

Which refer to

 function authentication(succes : boolean){
     if (succes) {
         googleAuthenticated = true;
         print("Loggato con: " + Social.localUser.userName + " ID: " + Social.localUser.id + " Minorenne: " + Social.localUser.underage);
     }
     else {
         googleAuthenticatedFailed = true;
         print("Non loggato");
     }
 }

Now, this was working perfectly, but when i added a keystore throught player settings, when i run the game on my device the authentication fails, is this a normal fact because i didn't download the game on play store or it is a issue? My game on the developer console is setted on beta version and my account is added as tester

Investigating on logcat i found the cause of the faluire:

 I/Unity   (22225):  [Play Games Plugin DLL] 03/09/15 20:24:07 +01:00 DEBUG: Star
 ting Auth Transition. Op: SIGN_IN status: ERROR_NOT_AUTHORIZED
 I/Unity   (22225):
 I/Unity   (22225): (Filename: ./artifacts/AndroidManagedGenerated/UnityEngineDeb
 ug.cpp Line: 49)
 I/Unity   (22225):
 I/Unity   (22225):  [Play Games Plugin DLL] 03/09/15 20:24:07 +01:00 DEBUG: Invo
 king user callback on game thread
 I/Unity   (22225):
 I/Unity   (22225): (Filename: ./artifacts/AndroidManagedGenerated/UnityEngineDeb
 ug.cpp Line: 49)
 I/Unity   (22225):
 I/Unity   (22225): Non loggato
 I/Unity   (22225):
 I/Unity   (22225): (Filename: ./artifacts/AndroidManagedGenerated/UnityEngineDeb
 ug.cpp Line: 49)
 I/Unity   (22225):
 D/dalvikvm(22225): threadid=15: thread exiting, not yet detached (count=0)

That SIGN_IN status: ERROR_NOT_AUTHORIZED seems to be the key, but what make it to appear?