Question My admob ads not showing

hi there,
My game that I use in the Play Store does not show admob ads either. Test ads were working fine on Unity and when I bought .apk.

my AdManager code is here :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using GoogleMobileAds.Api;
using System;

public class AdManager : MonoBehaviour
{
private InterstitialAd interstitialAd;
public BannerView _bannerView;

public static AdManager instance;
public void Start()
{
DontDestroyOnLoad(this.gameObject);
if(instance != null && instance != this)
{
Destroy(this.gameObject);
}
else
{
instance = this;
}
// Initialize the Google Mobile Ads SDK.
MobileAds.Initialize((InitializationStatus initStatus) =>
{
LoadInterstitialAd();
CreateBannerView();
LoadAd();
});
}
#region Interstitial
// These ad units are configured to always serve test ads.
#if UNITY_ANDROID
private string _adUnitId = "ca-app-pub-9324963738813081/3804090355";
#endif
/// <summary>
/// Loads the interstitial ad.
/// </summary>
public void LoadInterstitialAd()
{
// Clean up the old ad before loading a new one.
if (interstitialAd != null)
{
interstitialAd.Destroy();
interstitialAd = null;
}

Debug.Log("Loading the interstitial ad.");

// create our request used to load the ad.
var adRequest = new AdRequest();
adRequest.Keywords.Add("unity-admob-sample");

// send the request to load the ad.
InterstitialAd.Load(_adUnitId, adRequest,
(InterstitialAd ad, LoadAdError error) =>
{
// if error is not null, the load request failed.
if (error != null || ad == null)
{
Debug.LogError("interstitial ad failed to load an ad " +
"with error : " + error);
return;
}

Debug.Log("Interstitial ad loaded with response : "
+ ad.GetResponseInfo());

interstitialAd = ad;
RegisterEventHandlers(interstitialAd);
});
}
/// <summary>
/// Shows the interstitial ad.
/// </summary>
public void ShowAd()
{
if (interstitialAd != null && interstitialAd.CanShowAd())
{
Debug.Log("Showing interstitial ad.");
interstitialAd.Show();
}
else
{
Debug.LogError("Interstitial ad is not ready yet.");
}
}
private void RegisterEventHandlers(InterstitialAd ad)
{
// Raised when the ad is estimated to have earned money.
ad.OnAdPaid += (AdValue adValue) =>
{
Debug.Log(String.Format("Interstitial ad paid {0} {1}.",
adValue.Value,
adValue.CurrencyCode));
};
// Raised when an impression is recorded for an ad.
ad.OnAdImpressionRecorded += () =>
{
Debug.Log("Interstitial ad recorded an impression.");
};
// Raised when a click is recorded for an ad.
ad.OnAdClicked += () =>
{
Debug.Log("Interstitial ad was clicked.");
};
// Raised when an ad opened full screen content.
ad.OnAdFullScreenContentOpened += () =>
{
Debug.Log("Interstitial ad full screen content opened.");
};
// Raised when the ad closed full screen content.
ad.OnAdFullScreenContentClosed += () =>
{
Debug.Log("Interstitial ad full screen content closed.");
LoadInterstitialAd();
};
// Raised when the ad failed to open full screen content.
ad.OnAdFullScreenContentFailed += (AdError error) =>
{
Debug.LogError("Interstitial ad failed to open full screen content " +
"with error : " + error);
LoadInterstitialAd();
};
}
#endregion
#region Banner
// These ad units are configured to always serve test ads.
#if UNITY_ANDROID
private string _adUnitIdBanner = "ca-app-pub-9324963738813081/2362258004";
#endif

/// <summary>
/// Creates a 320x50 banner at top of the screen.
/// </summary>
public void CreateBannerView()
{
Debug.Log("Creating banner view");

// If we already have a banner, destroy the old one.
if (_bannerView != null)
{
DestroyAd();
}

// Create a 320x50 banner at top of the screen
_bannerView = new BannerView(_adUnitIdBanner, AdSize.Banner, AdPosition.Top);
}

/// <summary>
/// Creates the banner view and loads a banner ad.
/// </summary>
public void LoadAd()
{
// create an instance of a banner view first.
if (_bannerView == null)
{
CreateBannerView();
}
// create our request used to load the ad.
var adRequest = new AdRequest.Builder()
.AddKeyword("unity-admob-sample")
.Build();

// send the request to load the ad.
Debug.Log("Loading banner ad.");
_bannerView.LoadAd(adRequest);
ListenToAdEvents();
}

/// <summary>
/// listen to events the banner may raise.
/// </summary>
private void ListenToAdEvents()
{
// Raised when an ad is loaded into the banner view.
_bannerView.OnBannerAdLoaded += () =>
{
Debug.Log("Banner view loaded an ad with response : "
+ _bannerView.GetResponseInfo());
};
// Raised when an ad fails to load into the banner view.
_bannerView.OnBannerAdLoadFailed += (LoadAdError error) =>
{
Debug.LogError("Banner view failed to load an ad with error : "
+ error);
CreateBannerView();
LoadAd();
};
// Raised when the ad is estimated to have earned money.
_bannerView.OnAdPaid += (AdValue adValue) =>
{
Debug.Log(String.Format("Banner view paid {0} {1}.",
adValue.Value,
adValue.CurrencyCode));
};
// Raised when an impression is recorded for an ad.
_bannerView.OnAdImpressionRecorded += () =>
{
Debug.Log("Banner view recorded an impression.");
};
// Raised when a click is recorded for an ad.
_bannerView.OnAdClicked += () =>
{
Debug.Log("Banner view was clicked.");
};
// Raised when an ad opened full screen content.
_bannerView.OnAdFullScreenContentOpened += () =>
{
Debug.Log("Banner view full screen content opened.");
};
// Raised when the ad closed full screen content.
_bannerView.OnAdFullScreenContentClosed += () =>
{
Debug.Log("Banner view full screen content closed.");
};
}
/// <summary>
/// Destroys the ad.
/// </summary>
public void DestroyAd()
{
if (_bannerView != null)
{
Debug.Log("Destroying banner ad.");
_bannerView.Destroy();
_bannerView = null;
}
}
#endregion
}

and im get ads:
if (AdManager.instance._bannerView != null)
{
AdManager.instance._bannerView.Show();
if (adCount % 2 == 0)
{
AdManager.instance.ShowAd();
}
adCount++;
}