Admob for Unity app does not show add - unity3d

Question

I have a problem with admob for unity app, I used documentation to add admob, I used video tutorial from youtube and I tried demo app (hello world from admob), but the result is the same, ad banners does not appear in my apps, as for, if use interstitials, when I try to show it, my app crashes. However, in console there is a dummy message.
my code
using GoogleMobileAds.Api;
public class AdMobManager : MonoBehaviour {
private BannerView bannerView;
[SerializeField] private string appID = "";
[SerializeField] private string bannerID = "";
[SerializeField] private string regularAD = "";
private void Awake(){
MobileAds.Initialize(appID);
}
public void OnClickShowBanner() {
this.RequestBanner();
}
public void OnClickShowAd() {
this.RequestReqularAd();
}
private void RequestReqularAd() {
InterstitialAd AD = new InterstitialAd(regularAD);
AdRequest request = new AdRequest.Builder().Build();
AD.LoadAd(request);
}
public void RequestBanner() {
bannerView = new BannerView(bannerID, AdSize.Banner, AdPosition.Bottom);
AdRequest request = new AdRequest.Builder().Build();
bannerView.LoadAd(request);
}
}

Answer 1

You can use this simple code for admob banner. some time it takes time to display banner ad but this script worked fine.
Source
public class GoogleMobileAdsDemoScript : MonoBehaviour
{
private BannerView bannerView;
public void Start()
{
this.RequestBanner();
}
private void RequestBanner()
{
#if UNITY_ANDROID
string adUnitId = "ca-app-pub-3940256099942544/6300978111";
#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.Top);
// Create an empty ad request.
AdRequest request = new AdRequest.Builder().Build();
// Load the banner with the request.
bannerView.LoadAd(request);
}
}

Answer 2

Source code available https://github.com/unity-plugins/Unity-Admob/blob/master/AdmobPluginRes/admobdemo.cs
using UnityEngine;
using admob;
public class admobdemo : MonoBehaviour {
Admob ad;
string appID="";
string bannerID="";
string interstitialID="";
string videoID="";
string nativeBannerID = "";
void Start () {
Debug.Log("start unity demo-------------");
initAdmob();
}
void Update () {
if (Input.GetKeyUp (KeyCode.Escape)) {
Debug.Log(KeyCode.Escape+"-----------------");
}
}
void initAdmob()
{
#if UNITY_IOS
appID="ca-app-pub-3940256099942544~1458002511";
bannerID="ca-app-pub-3940256099942544/2934735716";
interstitialID="ca-app-pub-3940256099942544/4411468910";
videoID="ca-app-pub-3940256099942544/1712485313";
nativeBannerID = "ca-app-pub-3940256099942544/3986624511";
#elif UNITY_ANDROID
appID="ca-app-pub-3940256099942544~3347511713";
bannerID="ca-app-pub-3940256099942544/6300978111";
interstitialID="ca-app-pub-3940256099942544/1033173712";
videoID="ca-app-pub-3940256099942544/5224354917";
nativeBannerID = "ca-app-pub-3940256099942544/2247696110";
#endif
AdProperties adProperties = new AdProperties();
adProperties.isTesting = true;
ad = Admob.Instance();
ad.bannerEventHandler += onBannerEvent;
ad.interstitialEventHandler += onInterstitialEvent;
ad.rewardedVideoEventHandler += onRewardedVideoEvent;
ad.nativeBannerEventHandler += onNativeBannerEvent;
ad.initSDK(appID,adProperties);//reqired,adProperties can been null
}
void OnGUI(){
if (GUI.Button(new Rect(120, 0, 100, 60), "showInterstitial"))
{
Debug.Log("touch inst button -------------");
if (ad.isInterstitialReady())
{
ad.showInterstitial();
}
else
{
ad.loadInterstitial(interstitialID);
}
}
if (GUI.Button(new Rect(240, 0, 100, 60), "showRewardVideo"))
{
Debug.Log("touch video button -------------");
if (ad.isRewardedVideoReady())
{
ad.showRewardedVideo();
}
else
{
ad.loadRewardedVideo(videoID);
}
}
if (GUI.Button(new Rect(0, 100, 100, 60), "showbanner"))
{
Admob.Instance().showBannerRelative(bannerID,AdSize.SMART_BANNER, AdPosition.BOTTOM_CENTER);
}
if (GUI.Button(new Rect(120, 100, 100, 60), "showbannerABS"))
{
Admob.Instance().showBannerAbsolute(bannerID,AdSize.BANNER, 20, 220,"mybanner");
}
if (GUI.Button(new Rect(240, 100, 100, 60), "removebanner"))
{
Admob.Instance().removeBanner();
Admob.Instance().removeBanner("mybanner");
}
if (GUI.Button(new Rect(0, 200, 100, 60), "showNative"))
{
Admob.Instance().showNativeBannerRelative(nativeBannerID,new AdSize(320,280), AdPosition.BOTTOM_CENTER);
}
if (GUI.Button(new Rect(120, 200, 100, 60), "showNativeABS"))
{
Admob.Instance().showNativeBannerAbsolute(nativeBannerID,new AdSize(-1,132), 0, 300);
}
if (GUI.Button(new Rect(240, 200, 100, 60), "removeNative"))
{
Admob.Instance().removeNativeBanner();
}
}
void onInterstitialEvent(string eventName, string msg)
{
Debug.Log("handler onAdmobEvent---" + eventName + " " + msg);
if (eventName == AdmobEvent.onAdLoaded)
{
Admob.Instance().showInterstitial();
}
}
void onBannerEvent(string eventName, string msg)
{
Debug.Log("handler onAdmobBannerEvent---" + eventName + " " + msg);
}
void onRewardedVideoEvent(string eventName, string msg)
{
Debug.Log("handler onRewardedVideoEvent---" + eventName + " rewarded: " + msg);
}
void onNativeBannerEvent(string eventName, string msg)
{
Debug.Log("handler onAdmobNativeBannerEvent---" + eventName + " " + msg);
}
}