user can't log into google play services

User authentication doesn’t work in my app that I’m making for android. This is the script that is attached to an empty game object in my main menu.

void Start()
{

    PlayGamesPlatform.Activate();
    PlayGamesPlatform.DebugLogEnabled = true;

}

public void LoadScene(string sceneName)
{
    SceneManager.LoadScene(sceneName);
}

public void showleaderboard()
{
    if(Social.localUser.authenticated)
    {
        PlayGamesPlatform.Instance.ShowLeaderboardUI("CgkIq82p4qcNEAIQAQ");
    }
    else
    {
        Debug.Log("leaderboard not working");
    }
}

public void userlogin()
{
    Social.localUser.Authenticate((bool success) => 
    {
        if(success)
        {
            Debug.Log("Logged in");
        }
        else
        {
            Debug.Log("Login failed");
        }
    });
}

The functions are attached to buttons and I always get the log “Login Failed” in my console. I tested this on an android device that was able to log into google play services in other published apps.

u need to add your mail id in testers list !