AdMob real ads don't show but test ads work as expected

Hi all,

I recently learned how to setup ads on Unity using Admob. I've put my payment details, got a confirmation that my ad serving is enabled and tested with test ads (a banner, an interstitial and a rewarded video ad) and they work perfectly fine.

When I replaced the test adUnitId's with mine, built the application and downloaded it to my device, suddenly, the ads stopped appearing.

I searched for solutions, but none worked. So, what could cause this?

Here is my code, attached to my Game Control GameObject:

 using System;
 using UnityEngine;
 using UnityEngine.SceneManagement;
 using GoogleMobileAds.Api;
 
 public class GameControl : MonoBehaviour {
 
     bool hasSeenRBV = false;
 
     private BannerView bannerView;
     private InterstitialAd interstitial;
     private RewardedAd rewardedAd;
 
     void Start() {
         #if UNITY_EDITOR
             string appId = "unused";
         #elif UNITY_ANDROID
             string appId = "ca-app-pub-thisIsMyCorrect~appId";
         #elif UNITY_IPHONE
             string appId = "unexpected_platform";
         #else
             string appId = "unexpected_platform";
         #endif
 
         // Initialize the Google Mobile Ads SDK.
         MobileAds.Initialize(appId);
 
         this.RequestBanner();
         this.RequestInterstitial();
         this.CreateAndLoadRewardedAd();
     }
 
     private void RequestBanner()
     {
         #if UNITY_ANDROID
             string adUnitId = "ca-app-pub-thisIsTheCorrect~addUnitId";
         #elif UNITY_IPHONE
             string adUnitId = "unexpected_platform";
         #else
             string adUnitId = "unexpected_platform";
         #endif
             //string adUnitId = "ca-app-pub-3940256099942544/6300978111"; - test ads
 
         // Create a 320x50 banner at the top of the screen.
         bannerView = new BannerView(adUnitId, AdSize.Banner, AdPosition.Bottom);
 
         // Create an empty ad request.
         AdRequest request = new AdRequest.Builder().Build();
 
         // Load the banner with the request.
         bannerView.LoadAd(request);
     }
 
     private void RequestInterstitial()
     {
         #if UNITY_ANDROID
             string adUnitId = "ca-app-pub-thisIsTheCorrect~addUnitId";
         #elif UNITY_IPHONE
             string adUnitId = "unexpected_platform";
         #else
             string adUnitId = "unexpected_platform";
         #endif
             //string adUnitId = "ca-app-pub-3940256099942544/1033173712"; - test ads
 
         // Clean up interstitial ad before creating a new one.
         if (this.interstitial != null)
         {
             this.interstitial.Destroy();
         }
 
         // Create an interstitial.
         this.interstitial = new InterstitialAd(adUnitId);
 
         // Register for ad events.
         this.interstitial.OnAdLoaded += this.HandleInterstitialLoaded;
         this.interstitial.OnAdFailedToLoad += this.HandleInterstitialFailedToLoad;
         this.interstitial.OnAdOpening += this.HandleInterstitialOpened;
         this.interstitial.OnAdClosed += this.HandleInterstitialClosed;
         this.interstitial.OnAdLeavingApplication += this.HandleInterstitialLeftApplication;
 
         // Load an interstitial ad.
         AdRequest request = new AdRequest.Builder().Build();
         this.interstitial.LoadAd(request);
     }
 
     private void ShowInterstitial()
     {
         if (this.interstitial.IsLoaded())
         {
             this.interstitial.Show();
         }
         else
         {
             MonoBehaviour.print("Interstitial is not ready yet");
         }
     }
 
     public void CreateAndLoadRewardedAd()
     {
         #if UNITY_ANDROID
             string adUnitId = "ca-app-pub-thisIsTheCorrect~addUnitId";
         #elif UNITY_IPHONE
             string adUnitId = "unexpected_platform";
         #else
             string adUnitId = "unexpected_platform";
         #endif
             //string adUnitId = "ca-app-pub-3940256099942544/5224354917"; -- test ads
         // Create new rewarded ad instance.
         this.rewardedAd = new RewardedAd(adUnitId);
 
         // Called when an ad request has successfully loaded.
         this.rewardedAd.OnAdLoaded += HandleRewardedAdLoaded;
         // Called when an ad request failed to load.
         this.rewardedAd.OnAdFailedToLoad += HandleRewardedAdFailedToLoad;
         // Called when an ad is shown.
         this.rewardedAd.OnAdOpening += HandleRewardedAdOpening;
         // Called when an ad request failed to show.
         this.rewardedAd.OnAdFailedToShow += HandleRewardedAdFailedToShow;
         // Called when the user should be rewarded for interacting with the ad.
         this.rewardedAd.OnUserEarnedReward += HandleUserEarnedReward;
         // Called when the ad is closed.
         this.rewardedAd.OnAdClosed += HandleRewardedAdClosed;
 
         // Create an empty ad request.
         AdRequest request = new AdRequest.Builder().Build();
         // Load the rewarded ad with the request.
         this.rewardedAd.LoadAd(request);
     }
 
     private void ShowRewardedAd()
     {
         if (this.rewardedAd.IsLoaded())
         {
             this.rewardedAd.Show();
         }
         else
         {
             MonoBehaviour.print("Rewarded ad is not ready yet");
         }
     }
 
     public void StartGame() {
         if(PlayerPrefs.GetInt("tut") == 2) {
             SceneManager.LoadScene("Game");
         } else {
             PlayerPrefs.SetInt("tut", 2);
             SceneManager.LoadScene("Tutorial");
         }
     }
 
     public void RetryLevel() {
         int matchesTillLoadAd = PlayerPrefs.GetInt("mtla");
         if(matchesTillLoadAd == 3) {
             this.ShowInterstitial();
         } else {
             SceneManager.LoadScene("Game");
         }
         PlayerPrefs.SetInt("mtla", (matchesTillLoadAd + 1) % 4);
         //SceneManager.LoadScene("Game");
     }
 
     public void ToMainMenu() {
         SceneManager.LoadScene("Menu");
     }
 
     public void ToSkins() {
         SceneManager.LoadScene("Skins");
     }
 
     public void SaveColorByLoadingAd(int whatToDo) {
         ShowRewardedAd();
         /*GetComponent<SaveColor>().StoreChanges();/*
         if (rewardBasedVideo.IsLoaded()) {
             hasSeenRBV = false;
             rewardBasedVideo.Show();
             if(hasSeenRBV) {
                 if(whatToDo == 1) {
                     GetComponent<SaveColor>().StoreChanges();
                 }
             }
         }*/
     }
 
     public void HandleInterstitialLoaded(object sender, EventArgs args)
     {
         MonoBehaviour.print("HandleInterstitialLoaded event received");
     }
 
     public void HandleInterstitialFailedToLoad(object sender, AdFailedToLoadEventArgs args)
     {
         MonoBehaviour.print(
             "HandleInterstitialFailedToLoad event received with message: " + args.Message);
     }
 
     public void HandleInterstitialOpened(object sender, EventArgs args)
     {
         MonoBehaviour.print("HandleInterstitialOpened event received");
     }
 
     public void HandleInterstitialClosed(object sender, EventArgs args)
     {
         MonoBehaviour.print("HandleInterstitialClosed event received");
     }
 
     public void HandleInterstitialLeftApplication(object sender, EventArgs args)
     {
         MonoBehaviour.print("HandleInterstitialLeftApplication event received");
     }
 
     public void HandleRewardedAdLoaded(object sender, EventArgs args)
     {
         MonoBehaviour.print("HandleRewardedAdLoaded event received");
     }
 
     public void HandleRewardedAdFailedToLoad(object sender, AdErrorEventArgs args)
     {
         MonoBehaviour.print(
             "HandleRewardedAdFailedToLoad event received with message: " + args.Message);
     }
 
     public void HandleRewardedAdOpening(object sender, EventArgs args)
     {
         MonoBehaviour.print("HandleRewardedAdOpening event received");
     }
 
     public void HandleRewardedAdFailedToShow(object sender, AdErrorEventArgs args)
     {
         MonoBehaviour.print(
             "HandleRewardedAdFailedToShow event received with message: " + args.Message);
     }
 
     public void HandleRewardedAdClosed(object sender, EventArgs args)
     {
         MonoBehaviour.print("HandleRewardedAdClosed event received");
     }
 
     public void HandleUserEarnedReward(object sender, Reward args)
     {
         string type = args.Type;
         double amount = args.Amount;
         MonoBehaviour.print(
             "HandleRewardedAdRewarded event received for "
                         + amount.ToString() + " " + type);
         GetComponent<SaveColor>().StoreChanges();
     }
 }