Game doesnt start after adding Admob

Game doesnt start after adding Admob, in the Unity everything forks fine, but when im building game to android and open it - there just a black screen. Here’s my script, which i added to empty GameObject.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using GoogleMobileAds.Api;
using GoogleMobileAds;
public class AdBannder : MonoBehaviour
{
private BannerView bannerView;

public void Start()
{
    #if UNITY_ANDROID
        string appId = "ca-app-pub-3945473749443628~7640216171";
    #elif UNITY_IPHONE
        string appId = "ca-app-pub-3940256099942544~1458002511";
    #else
        string appId = "unexpected_platform";
    #endif

    // Initialize the Google Mobile Ads SDK.
    MobileAds.Initialize(appId);

    this.RequestBanner();
}

private void RequestBanner()
{
    #if UNITY_ANDROID
        string adUnitId = "ca-app-pub-3945473749443628/1192736638";
    #elif UNITY_IPHONE
        string adUnitId = "ca-app-pub-3940256099942544/2934735716";
    #else
        string adUnitId = "unexpected_platform";
    #endif

    // Create a 320x50 banner at the top of the screen.
    bannerView = new BannerView(adUnitId, AdSize.Banner, AdPosition.Bottom);
}

}

Did you add the app id in Manifest file?