Unity Ads rewarded video no result, Android

I get no response after rewarded video on android, test mode enabled or not I'm not geting any result The projects is linked with the Google Play ID

I'm using unity 5.5.0.p3 and the builtin ads (it doesn't recognize if I import them from the store)

What can I do?

I'm using the code from samples

 public void showRewardedVideo(){
     if(Advertisement.IsReady("rewardedVideo")){
         var options = new ShowOptions { resultCallback = HandleShowResult };
     also tried with
     ShowOptions options = new ShowOptions();
     options.resultCallback = HandleShowResult;
         Advertisement.Show("rewardedVideo", options);
     }
 }
 private void HandleShowResult(ShowResult result){
     debugText.text = "ads rez: " + result.ToString ();
     switch (result){
         case ShowResult.Finished:
             updateBonusScore(20, true);
             break;
         case ShowResult.Skipped:
             Debug.Log("The ad was skipped before reaching the end.");
             break;
         case ShowResult.Failed:
             Debug.LogError("The ad failed to be shown.");
             break;
     }
 }