Google Play services Login fails everytime??

I know that this doesnt work in the editor but im Getting this error and its not working on the phone either.

Login failed
UnityEngine.Debug:Log(Object)
GPGDemo:<LogIn>m__2(Boolean) (at Assets/GPGDemo.cs:52)
GooglePlayGames.<Authenticate>c__AnonStorey0:<>m__0(Boolean, String) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:383)
GooglePlayGames.BasicApi.DummyClient:Authenticate(Action`2, Boolean) (at Assets/GooglePlayGames/BasicApi/DummyClient.cs:50)
GooglePlayGames.PlayGamesPlatform:Authenticate(Action`2, Boolean) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:414)
GooglePlayGames.PlayGamesPlatform:Authenticate(Action`1, Boolean) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:383)
GooglePlayGames.PlayGamesPlatform:Authenticate(Action`1) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:348)
GooglePlayGames.PlayGamesLocalUser:Authenticate(Action`1) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesLocalUser.cs:49)
GPGDemo:LogIn() (at Assets/GPGDemo.cs:43)
GPGDemo:Start() (at Assets/GPGDemo.cs:32)

And Here is my Code:

using UnityEngine;
using System.Collections;
using GooglePlayGames;
using UnityEngine.SocialPlatforms;
public class GPGDemo : MonoBehaviour
{
    #region PUBLIC_VAR
    
    #endregion
    #region DEFAULT_UNITY_CALLBACKS
    void Start()
    {
        // recommended for debugging:
        PlayGamesPlatform.DebugLogEnabled = true;

        // Activate the Google Play Games platform
        PlayGamesPlatform.Activate();
        if(Social.localUser.authenticated)
        {
              Social.ReportScore(PlayerPrefs.GetInt("Highsore"), GPGSIds.leaderboard_normal_highscores, (bool success) =>
              {

              });
              Social.ReportScore(PlayerPrefs.GetInt("Highsore Bitz"), GPGSIds.leaderboard_fast_highscores, (bool success) =>
              {

              });

        }
        else
        {
            LogIn();
        }
       
    }
    #endregion
    #region BUTTON_CALLBACKS
    /// <summary>
    /// Login In Into Your Google+ Account
    /// </summary>
    public void LogIn()
    {
        Social.localUser.Authenticate((bool success) =>
        {
            if (success)
            {
                Debug.Log("Login Sucess");
                OnAuthenticated();
            }
            else
            {
                Debug.Log("Login failed");
            }
        });
    }
    public void OnAuthenticated()
    {
        Social.ReportScore(PlayerPrefs.GetInt("Highsore"), GPGSIds.leaderboard_normal_highscores, (bool success) =>
        {

        });
        Social.ReportScore(PlayerPrefs.GetInt("Highsore Bitz"), GPGSIds.leaderboard_fast_highscores, (bool success) =>
        {

        });
    }
    /// <summary>
    /// Shows All Available Leaderborad
    /// </summary>
    public void OnShowLeaderBoard()
    {
        //        Social.ShowLeaderboardUI (); // Show all leaderboard
        if(Social.localUser.authenticated)
        ((PlayGamesPlatform)Social.Active).ShowLeaderboardUI(); // Show current (Active) leaderboard
    }
    /// <summary>
    /// Adds Score To leader board
    /// </summary>
    
    /// <summary>
    /// On Logout of your Google+ Account
    /// </summary>
    public void OnLogOut()
    {
        ((PlayGamesPlatform)Social.Active).SignOut();
    }
    #endregion
}

im calling the OnShowLeaderboard void with a button

@Frieder_Mueller have you found solution to this?

I’m having identical problem at identical lines

login fail.
UnityEngine.Debug:LogWarning(Object)
PlayGamesController:b__3_0(Boolean) (at Assets/Graph/Scripts/PlayGamesController.cs:58)
GooglePlayGames.<>c__DisplayClass37_0:b__0(Boolean, String) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:383)
GooglePlayGames.BasicApi.DummyClient:Authenticate(Action2, Boolean) (at Assets/GooglePlayGames/BasicApi/DummyClient.cs:50) GooglePlayGames.PlayGamesPlatform:Authenticate(Action2, Boolean) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:414)
GooglePlayGames.PlayGamesPlatform:Authenticate(Action1, Boolean) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:383) GooglePlayGames.PlayGamesPlatform:Authenticate(Action1) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesPlatform.cs:348)
GooglePlayGames.PlayGamesLocalUser:Authenticate(Action`1) (at Assets/GooglePlayGames/ISocialPlatform/PlayGamesLocalUser.cs:49)
PlayGamesController:AuthenticateUser() (at Assets/Graph/Scripts/PlayGamesController.cs:50)
PlayGamesController:Start() (at Assets/Graph/Scripts/PlayGamesController.cs:29)