Unity Admob Ödüllü Reklam Gözükmüyor

    public void ShowRewardedAd()
    {
        const string rewardMsg =
            "Rewarded ad rewarded the user. Type: {0}, amount: {1}.";

        if (_rewardedAd != null && _rewardedAd.CanShowAd())
        {
            _rewardedAd.Show((Reward reward) =>
            {
                GameManager.isGameOver = false;
            });
        }
    }