Bug When ad must show, game crashes [Android, AdMob]

I'm making game for android with AdMob. In editor ad is showing, but on release on ad showing moment game crashes.

Unity version: 2021.3.14f1
AdMob version: 7.4.0

Here code:

Code (CSharp):

1. using UnityEngine;
2. using GoogleMobileAds.Api;
3.  
4. public class AdManager : MonoBehaviour
5. {
6.     [SerializeField] private string idAd;
7.  
8.     private int adShowedCounter = 0;
9.     [SerializeField, Min(1)] private int adShowingIteration = 2;
10.  
11.     public static AdManager Instance = new AdManager();
12.  
13.     private InterstitialAd interstitial;
14.  
15.     public void ShowAd()
16.     {
17.         adShowedCounter++;
18.  
19.         if (interstitial != null)
20.         {
21.             interstitial.Destroy();
22.             interstitial = null;
23.         }
24.  
25.         if (adShowedCounter >= adShowingIteration)
26.         {
27.             InterstitialAd.Load(idAd, new AdRequest.Builder().Build(), (ad, err) =>
28.             {
29.                 if (err != null || ad == null)
30.                 {
31.                     Debug.LogError(err.GetMessage());
32.  
33.                     return;
34.                 }
35.  
36.                 interstitial = ad;
37.             });
38.  
39.             adShowedCounter = 0;
40.         }
41.  
42.         if (interstitial != null && interstitial.CanShowAd())
43.             interstitial.Show();
44.         else
45.             Debug.LogError("Advertisement is not ready");
46.     }
47. }

 

Any Errors via LogCat? Only thing that stands out to me is a potential nullref in

Debug.LogError(err.GetMessage());

(if ad == null && err == null)

 

Can you say how to use LogCat?

 

1. Enable USB debugging on the device (under Developer Settings).
2. Connect device to PC via USB
3. Build & Run a debug-build
4. open a command prompt, and run 'adb logcat'.
this will give you a console-output for your device.

Many videos for this on YouTube if this is hard to understand.
Here's a random one: Realtime Debugging for Unity Android Apps - ADB LogCat Tutorial - YouTube

 

Here:

Code (CSharp):

1. 02-16 13:11:08.617 13524 13571 E Unity   : Advertisement is not ready
2. 02-16 13:11:08.617 13524 13571 E Unity   : Puzzlemanager:SelectNextLevel()
3. 02-16 13:11:08.617 13524 13571 E Unity   : UnityEngine.Events.UnityEvent:Invoke()
4. 02-16 13:11:08.617 13524 13571 E Unity   : UnityEngine.EventSystems.ExecuteEvents:Execute(GameObject, BaseEventData, EventFunction`1)
5. 02-16 13:11:08.617 13524 13571 E Unity   : UnityEngine.EventSystems.StandaloneInputModule:ProcessTouchPress(PointerEventData, Boolean, Boolean)
6. 02-16 13:11:08.617 13524 13571 E Unity   : UnityEngine.EventSystems.StandaloneInputModule:ProcessTouchEvents()
7. 02-16 13:11:08.617 13524 13571 E Unity   : UnityEngine.EventSystems.StandaloneInputModule:Process()
8. 02-16 13:11:08.617 13524 13571 E Unity   :

 

I forgot to write that ads should be displayed several times in one scene