GoogleSignInResult isSuccess funktioniert nicht

Schönen Guten Tag,
ich möchte den Google Login für meine App nutzen, aber leider bekomme ich die Fehlermeldung Status{statusCode=unknown status code: 12500, resolution=null
Ich habe schon alles Mögliche versucht, aber leider finde ich kein Lösung zu meinem Problem.
Hier mein Quellcode der Activity:

package de.lernapp.lernApp;

import android.app.ProgressDialog;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.TextView;

import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.auth.api.signin.GoogleSignInResult;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.SignInButton;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.OptionalPendingResult;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.common.api.Status;

import de.lernapp.R;
import de.lernapp.datenbank.LernAppDB;
import de.lernapp.datenbank.ZentraleDB;

public class GruppenActivity extends AppCompatActivity implements
GoogleApiClient.OnConnectionFailedListener,
View.OnClickListener {

private static final String TAG = "SignInActivity";
private static final int RC_SIGN_IN = 9001;

private GoogleApiClient mGoogleApiClient;
private TextView mStatusTextView;
private ProgressDialog mProgressDialog;

private LernAppDB db;
private SQLiteDatabase sqlDatabase;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_gruppen);

    // Views
    mStatusTextView = (TextView) findViewById(R.id.status);

    // Button listeners
    findViewById(R.id.sign_in_button).setOnClickListener(this);
    findViewById(R.id.sign_out_button).setOnClickListener(this);
    findViewById(R.id.disconnect_button).setOnClickListener(this);

    db = new LernAppDB(this);
    sqlDatabase = db.getReadableDatabase();


    GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
            .requestEmail()
            .requestIdToken(getString(R.string.server_client_id))
            .requestServerAuthCode(getString(R.string.server_client_id))
            .build();

    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .enableAutoManage(this , this )
            .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
            .build();

    SignInButton signInButton = (SignInButton) findViewById(R.id.sign_in_button);
    signInButton.setSize(SignInButton.SIZE_STANDARD);
    signInButton.setScopes(gso.getScopeArray());

}

@Override
public void onStart() {
    super.onStart();

    OptionalPendingResult<GoogleSignInResult> opr = Auth.GoogleSignInApi.silentSignIn(mGoogleApiClient);
    if (opr.isDone()) {
        Log.d(TAG, "Got cached sign-in");
        GoogleSignInResult result = opr.get();
        handleSignInResult(result);
    } else {

        showProgressDialog();
        opr.setResultCallback(new ResultCallback<GoogleSignInResult>() {
            @Override
            public void onResult(GoogleSignInResult googleSignInResult) {
                hideProgressDialog();
                handleSignInResult(googleSignInResult);
            }
        });
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == RC_SIGN_IN) {
        GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
        handleSignInResult(result);
    }
}

private void handleSignInResult(GoogleSignInResult result) {
    Log.d(TAG, "handleSignInResult:" + result.isSuccess());
    if (result.isSuccess()) {
        // Signed in successfully, show authenticated UI.
        GoogleSignInAccount acct = result.getSignInAccount();
        String personName = acct.getDisplayName();
        String personEmail = acct.getEmail();
        ZentraleDB zentraleDB = new ZentraleDB();
        zentraleDB.benutzerAnlegen(sqlDatabase,personEmail,"hans","wilhelm",personName,"tesr");
        mStatusTextView.setText(getString(R.string.signed_in_fmt, acct.getDisplayName()));
        updateUI(true);
    } else {
        updateUI(false);
    }
}

private void signIn() {
    Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
    startActivityForResult(signInIntent, RC_SIGN_IN);


}

private void signOut() {
    Auth.GoogleSignInApi.signOut(mGoogleApiClient).setResultCallback(
            new ResultCallback<Status>() {
                @Override
                public void onResult(Status status) {
                    // [START_EXCLUDE]
                    updateUI(false);
                    // [END_EXCLUDE]
                }
            });
}

private void revokeAccess() {
    Auth.GoogleSignInApi.revokeAccess(mGoogleApiClient).setResultCallback(
            new ResultCallback<Status>() {
                @Override
                public void onResult(Status status) {
                    updateUI(false);
                }
            });
}

@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
    Log.d(TAG, "onConnectionFailed:" + connectionResult);
}

private void showProgressDialog() {
    if (mProgressDialog == null) {
        mProgressDialog = new ProgressDialog(this);
        mProgressDialog.setMessage(getString(R.string.loading));
        mProgressDialog.setIndeterminate(true);
    }

    mProgressDialog.show();
}

private void hideProgressDialog() {
    if (mProgressDialog != null && mProgressDialog.isShowing()) {
        mProgressDialog.hide();
    }
}

private void updateUI(boolean signedIn) {
    if (signedIn) {
        findViewById(R.id.sign_in_button).setVisibility(View.GONE);
        findViewById(R.id.sign_out_and_disconnect).setVisibility(View.VISIBLE);
    } else {
        mStatusTextView.setText(R.string.signed_out);

        findViewById(R.id.sign_in_button).setVisibility(View.VISIBLE);
        findViewById(R.id.sign_out_and_disconnect).setVisibility(View.GONE);
    }
}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.sign_in_button:
            signIn();
            break;
        case R.id.sign_out_button:
            signOut();
            break;
        case R.id.disconnect_button:
            revokeAccess();
            break;
    }
}

}

Könnte mir jemand Helfen?