Reward video doesn't work (Admob)

Hello guys , i just trying to make ad showing when i press a button , and receive some coins back(in my case) .
This is my video reward script button . In Console its seem to be all okay , i will put a picture . I test also on my phone , when i press that button i receive a small message back with (AD IS NOT AVAILABLE AT THE MOMENT) . Thanks a lot for any help …

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

public class RewardedVideoButton : MonoBehaviour
{
    private const string ACTION_NAME = "rewarded_video";

    private void Start()
    {
        Timer.Schedule(this, 0.1f, AddEvents);
    }

    private void AddEvents()
    {
#if UNITY_ANDROID || UNITY_IOS
        if (AdmobController.instance.rewardBasedVideo != null)
        {
            AdmobController.instance.rewardBasedVideo.OnAdRewarded += HandleRewardBasedVideoRewarded;
        }
#endif
    }

    public void OnClick()
    {
        if (IsAvailableToShow())
            AdmobController.instance.ShowRewardBasedVideo();
        else if (!IsAdAvailable())
            Toast.instance.ShowMessage("Ad is not available at the moment");
        else
        {
            int remainTime = (int)(GameConfig.instance.rewardedVideoPeriod - CUtils.GetActionDeltaTime(ACTION_NAME));
            Toast.instance.ShowMessage("Please wait " + remainTime + " seconds for the next ad");
        }
    }

    public void HandleRewardBasedVideoRewarded(object sender, Reward args)
    {

    }

    public bool IsAvailableToShow()
    {
        return IsActionAvailable() && IsAdAvailable();
    }

    private bool IsActionAvailable()
    {
        return CUtils.IsActionAvailable(ACTION_NAME, GameConfig.instance.rewardedVideoPeriod);
    }

    private bool IsAdAvailable()
    {
        if (AdmobController.instance.rewardBasedVideo == null) return false;
        bool isLoaded = AdmobController.instance.rewardBasedVideo.IsLoaded();
        return isLoaded;
    }

    private void OnDestroy()
    {
#if UNITY_ANDROID || UNITY_IOS
        if (AdmobController.instance.rewardBasedVideo != null)
        {
            AdmobController.instance.rewardBasedVideo.OnAdRewarded -= HandleRewardBasedVideoRewarded;
        }
#endif
    }
}

i’m stuck here … today i try to import again plugin , but the same result …

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