Google Play Services show leaderboard

I'm trying to implement the Google Play Services into game. I've followed this guide: https://github.com/playgameservices/play-games-plugin-for-unity

I've followed the setup instructions for the Play console, and I have setup my game inside Play Console (play.google.com/apps/publish). I have set a test account up, which I'm currently using. I don't know what I did wrong, but I havn't used the Signing Certificate fingerprint (SHA1) at all.

I am currently using a version of my APK, that isn't on the play store, because of testing.

I am able to sign in just fine, but the report score doesn't work as it should. Nor does the ShowLeaderBoardUI. I have tried different things, but this is my current version of the code:

 if(GUI.Button(new Rect (Screen.width/2 - 105*u, Screen.height/3 + 450*u, 210*u, 210*u), "Score")){
                 // Activate the Google Play Games platform
                 PlayGamesPlatform.DebugLogEnabled = true; 
                 PlayGamesPlatform.Activate();
                 Social.localUser.Authenticate((bool success) => {
                     if(success){
                         Social.ReportScore(PlayerPrefs.GetInt ("best"), "CxxxxQ", (bool s) => {
                                 ((PlayGamesPlatform) Social.Active).ShowLeaderboardUI("CxxxxQ");
                         });
                     } else {
                         print ("Did not authenciate.");
                     }
                 });
             }

I have tried the following two versions too:

 Social.ReportScore(PlayerPrefs.GetInt ("best"), "CxxxxQ", (bool s) => {
                             if(s) {
                                 ((PlayGamesPlatform) Social.Active).ShowLeaderboardUI("CxxxxQ");
                             } else {
                                 print ("Something went wrong");
                             }
                                 
                         });

and

 Social.localUser.Authenticate((bool success) => {
                     if(success){
                         Social.ReportScore(PlayerPrefs.GetInt ("best"), "CxxxxQ", (bool s) => {
                             if(s) {
                                 ((PlayGamesPlatform) Social.Active).ShowLeaderboardUI("CxxxxQ");
                             } else {
                                 print ("Something went wrong");
                                 //Just to test if it's called, since I can't see the print
                                 Application.LoadLevel(Application.loadedLevel);
                             }
                                 
                         });

None of them are called however, and I can't see why not?