May I ask why scrpt cannot be triggered after watching the advertisement?,May I ask why [HandleOnAdRewarded] cannot be triggered after watching the advertisement?

May I ask why [HandleOnAdRewarded] cannot be triggered after watching the advertisement?

this is script using UnityEngine; using GoogleMobileAds.Api; using System; using UnityEngine.UI; //reward ad

public class ad : MonoBehaviour { private RewardBasedVideoAd adReward;

 private string idApp, idReward;

 [SerializeField] Button BtnReward;
 [SerializeField] Text TxtPoints;
 public Text text2;

 void Start ()
 {
     idApp = "ca-app-pub-3940256099942544~3347511713";
     idReward = "ca-app-pub-3940256099942544/5224354917";

     adReward = RewardBasedVideoAd.Instance;

     MobileAds.Initialize (idApp);
 }


 #region Reward video methods ---------------------------------------------

 public void RequestRewardAd ()
 {
     AdRequest request = AdRequestBuild ();
     adReward.LoadAd (request, idReward);

     adReward.OnAdLoaded += this.HandleOnRewardedAdLoaded;
     adReward.OnAdRewarded += this.HandleOnAdRewarded;
     adReward.OnAdClosed += this.HandleOnRewardedAdClosed;
 }

 public void ShowRewardAd ()
 {
     if (adReward.IsLoaded ())
         adReward.Show ();
 }
 //events
 public void HandleOnRewardedAdLoaded (object sender, EventArgs args)
 {//ad loaded
     ShowRewardAd ();

 }

 public void HandleOnAdRewarded (object sender, EventArgs args)
 {//user finished watching ad
     int points = int.Parse (TxtPoints.text);
     points += 50; //add 50 points
     text2.text = ("5");
     TxtPoints.text = points.ToString ();

     var coint = GameObject.Find("CoinManager").GetComponent<CoinManager>();
     coint.AddCoint(coint.scord);
 }

 public void HandleOnRewardedAdClosed (object sender, EventArgs args)
 {//ad closed (even if not finished watching)
     BtnReward.interactable = true;
     BtnReward.GetComponentInChildren <Text> ().text = "More Points";

     adReward.OnAdLoaded -= this.HandleOnRewardedAdLoaded;
     adReward.OnAdRewarded -= this.HandleOnAdRewarded;
     adReward.OnAdClosed -= this.HandleOnRewardedAdClosed;
 }

 #endregion

 //other functions
 //btn (more points) clicked
 public void OnGetMorePointsClicked ()
 {
     BtnReward.interactable = false;
     BtnReward.GetComponentInChildren <Text> ().text = "Loading...";
     RequestRewardAd ();
 }

 //------------------------------------------------------------------------
 AdRequest AdRequestBuild ()
 {
     return new AdRequest.Builder ().Build ();
 }

 void OnDestroy ()
 {
     adReward.OnAdLoaded -= this.HandleOnRewardedAdLoaded;
     adReward.OnAdRewarded -= this.HandleOnAdRewarded;
     adReward.OnAdClosed -= this.HandleOnRewardedAdClosed;
 }

} , May I ask why [HandleOnAdRewarded] cannot be triggered after watching the advertisement? this is script

//reward ad public class ad : MonoBehaviour { private RewardBasedVideoAd adReward;

 private string idApp, idReward;

 [SerializeField] Button BtnReward;
 [SerializeField] Text TxtPoints;
 public Text text2;

 void Start ()
 {
     idApp = "";
     idReward = "ca-app-pub-3940256099942544/5224354917";

     adReward = RewardBasedVideoAd.Instance;

     MobileAds.Initialize (idApp);
 }


 #region Reward video methods ---------------------------------------------

 public void RequestRewardAd ()
 {
     AdRequest request = AdRequestBuild ();
     adReward.LoadAd (request, idReward);

     adReward.OnAdLoaded += this.HandleOnRewardedAdLoaded;
     adReward.OnAdRewarded += this.HandleOnAdRewarded;
     adReward.OnAdClosed += this.HandleOnRewardedAdClosed;
 }

 public void ShowRewardAd ()
 {
     if (adReward.IsLoaded ())
         adReward.Show ();
 }
 //events
 public void HandleOnRewardedAdLoaded (object sender, EventArgs args)
 {//ad loaded
     ShowRewardAd ();

 }

 public void HandleOnAdRewarded (object sender, EventArgs args)
 {//user finished watching ad
     int points = int.Parse (TxtPoints.text);
     points += 50; //add 50 points
     text2.text = ("5");
     TxtPoints.text = points.ToString ();

     var coint = GameObject.Find("CoinManager").GetComponent<CoinManager>();
     coint.AddCoint(coint.scord);
 }

 public void HandleOnRewardedAdClosed (object sender, EventArgs args)
 {//ad closed (even if not finished watching)
     BtnReward.interactable = true;
     BtnReward.GetComponentInChildren <Text> ().text = "More Points";

     adReward.OnAdLoaded -= this.HandleOnRewardedAdLoaded;
     adReward.OnAdRewarded -= this.HandleOnAdRewarded;
     adReward.OnAdClosed -= this.HandleOnRewardedAdClosed;
 }

 #endregion

 //other functions
 //btn (more points) clicked
 public void OnGetMorePointsClicked ()
 {
     BtnReward.interactable = false;
     BtnReward.GetComponentInChildren <Text> ().text = "Loading...";
     RequestRewardAd ();
 }

 //------------------------------------------------------------------------
 AdRequest AdRequestBuild ()
 {
     return new AdRequest.Builder ().Build ();
 }

 void OnDestroy ()
 {
     adReward.OnAdLoaded -= this.HandleOnRewardedAdLoaded;
     adReward.OnAdRewarded -= this.HandleOnAdRewarded;
     adReward.OnAdClosed -= this.HandleOnRewardedAdClosed;
 }

}