Google Play Services doesnt work

Unity Engine
,
1

Hey,
I got some problems with my game and connecting it to Google Play Services.
I got all the SDK stuff installed and Keystore set up.
I havent used Google Play Services before.
Thats the funktion that should connect it to Google. Im calling it at the start and some useractions but no UI from google is showing up.

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

Does somebody have any idea why it doesnt work?
I would appreciate if you would help me.
Hollo1001

2

Does it print anything at all to the log at this point ?