Google Admob interstitial ad not showing + please check my code

Dear Forum members!

Please help me, I implemented the Unity Google Plugin with no errors. After I wrote the codes, and debugged, but the interstitial ad not showing. I don't understand what could be a problem. Thank you very much in advance!

Here is my code:

Code (csharp):

1.  -----------
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using GoogleMobileAds.Api;
6. using System;
7.  
8.  
9. public class admobstuff : MonoBehaviour {
10.     public void Start()
11.     {
12.  #if UNITY_ANDROID
13.                 string appId = "ca-app-pub-3940256099942544~3347511713";
14. #elif UNITY_IPHONE
15.                     string appId = "ca-app-pub-3940256099942544~1458002511";
16. #else
17.                     string appId = "unexpected_platform";
18. #endif
19.  
20.         // Initialize the Google Mobile Ads SDK.
21.         MobileAds.Initialize(appId);
22.     }
23.     string adUnitId = "ca-app-pub-3940256099942544/1033173712";
24.  
25.     private void RequestInterstitial()
26.     {
27.  #if UNITY_ANDROID
28.                  adUnitId = "ca-app-pub-3940256099942544/1033173712";                                                            
29. #elif UNITY_IPHONE
30.                  adUnitId = "ca-app-pub-3940256099942544/4411468910";
31. #else
32.                  adUnitId = "unexpected_platform";
33. #endif
34.  
35.         // Initialize an InterstitialAd.
36.  
37.     }
38.  
39.     InterstitialAd myadd = null;
40.     public void CreateAnAd()
41.     {
42.         if (myadd != null)
43.         {
44.             myadd.Destroy();
45.             myadd = null;
46.         }
47.  
48.         RequestInterstitial();
49.  
50.         myadd = new InterstitialAd(adUnitId);
51.         AdRequest request = new AdRequest.Builder().Build();
52.         // Load the interstitial with the request.
53.         myadd.LoadAd(request);
54.  
55.         if (myadd.IsLoaded())
56.         {
57.             myadd.Show();
58.         }
59.  
60.     }
61.  
62.     public void OnGUI()
63.     {
64.         if(myadd != null)
65.         {
66.             float buttonWidth = 0.15f * Screen.width;
67.             float buttonHeight = 0.15f * Screen.width;
68.             Rect destroyInterstitialRect = new Rect(
69.               0.01f * Screen.width,
70.             0.01f * Screen.width,
71.             buttonWidth,
72.                buttonHeight);
73.             if (GUI.Button(destroyInterstitialRect, "X"))
74.             {
75.                 this.myadd.Destroy();
76.                 myadd = null;
77.                 GameObject[] gameaa = GameObject.FindGameObjectsWithTag("WinsLoses");
78.                 foreach (var item in gameaa)
79.                 {
80.                    if(item.GetComponent<WinTheGameWindow>() != null)
81.                     {
82.                         item.GetComponent<WinTheGameWindow>().DestroyedTheAd();
83.                     }
84.                     if (item.GetComponent<LostTheGameWindow>() != null)
85.                     {
86.                         item.GetComponent<LostTheGameWindow>().DestroyedTheAd();
87.                     }
88.                 }
89.             }
90.         }
91.  
92.  
93.     }
94. }
95.  
96.  
97. ----------------------------------------
98.  

 

Use code tags. https://forum.unity.com/threads/using-code-tags-properly.143875/