Unity广告通常不会展示真实广告

Question

我设置了一个统一的广告代码来显示奖励视频，但是当我按下一个按钮时，当我按下20到50次时，它只会显示一个，每次按下时，它应该向我显示，我想知道是什么问题 ，这是我的代码：

public static AdController instance;
private string store_id = "0000000";//000000 is not my real id
private string video_id = "video";
private string rewarded_video_id = "rewardedVideo";
private void Awake () {
    if (instance != null) {
        Destroy (gameObject);
    } else {
        instance = this;
        DontDestroyOnLoad (gameObject);
    }
}
void Start () {
    Monetization.Initialize (store_id, true);

}


public void ShowRewardedvideo () {
    if (Monetization.IsReady (rewarded_video_id)) {

        ShowAdPlacementContent ad = null;
        ad = Monetization.GetPlacementContent (rewarded_video_id) as ShowAdPlacementContent;

        if (ad != null) {
            ad.Show ();
        }
    }
}
public void Showvideo () {
    if (Monetization.IsReady (video_id)) {

        ShowAdPlacementContent ad = null;
        ad = Monetization.GetPlacementContent (video_id) as ShowAdPlacementContent;

        if (ad != null) {
            ad.Show ();
        }
    }
}