Admob - interstitial doesnt work.

Hello,
im trying to add a google interstitial at my project but somehow it doesnt show up.
Banners showing up without a problem,but for test purposes i deactivted the banner.

Test script attached on my main camera :

using GoogleMobileAds.Api;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class AdScript : MonoBehaviour {

    public bool showint;
    // Use this for initialization
    void Start () {
        RequestInterstitialAds ();
        //showBannerAd();
        showint = true;

    }

    private void showBannerAd()
    {
        string adID = "myadid";

        //Testing
        AdRequest request = new AdRequest.Builder()
            .AddTestDevice(AdRequest.TestDeviceSimulator)       // Simulator.
            .AddTestDevice("9C99086DFF14F4B8")  // My test device.
            .Build();

        // normal
        //AdRequest request = new AdRequest.Builder().Build();

        BannerView bannerAd = new BannerView(adID, AdSize.SmartBanner, AdPosition.Top);
        bannerAd.LoadAd(request);
    }

    // Update is called once per frame
    void Update () {
        if (showint == true) {
            showInterstitialAD ();
            showint = false;
      
        }
    }




    //AD
    InterstitialAd interstitial;
    private void RequestInterstitialAds()
    {
        string adID = "myADID";

        #if UNITY_ANDROID
        string adUnitId = adID;
        #elif UNITY_IOS
        string adUnitId = adID;
        #else
        string adUnitId = adID;
        #endif

        // Initialize an InterstitialAd.
        interstitial = new InterstitialAd(adUnitId);

        //Test
        AdRequest request = new AdRequest.Builder()
        .AddTestDevice(AdRequest.TestDeviceSimulator)       // Simulator.
        .AddTestDevice("9C99086DFF14F4B8")  // My test device.
        .Build();

        //normal
        //AdRequest request = new AdRequest.Builder().Build();

 

        // Load the interstitial with the request.
        interstitial.LoadAd(request);

   

        }

        public void showInterstitialAD(){

        if (interstitial.IsLoaded ()) {
        interstitial.Show ();

        }

        }






}

I also tried to add it to the normal game,after u died and before u get to the highscore scene.

public void tohighscore(){
        RequestInterstitialAds();
        showInterstitialAD ();
            SceneManager.LoadScene ("Highscore", LoadSceneMode.Single);


    }

Theres a button which activates the method “tohighscore”. Doesnt work aswell…

Perhaps this vid can help you out: Rewarded ads  |  Unity  |  Google for Developers

Cheers!