Difficulty with Reward Ads example

I'm trying to follow the Unity Ads Quick Start Guide to incorporate reward ads into my game. Basically, you click a UI button and it gives the player an extra bit of health. But, when I press play and click the button, nothing happens. I appreciate any assistance. Here is my code:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.Advertisements;
5.  
6. public class showrewardad : MonoBehaviour
7. {
8.  
9.     public void ShowRewardedAd()
10.     {
11.         if (Advertisement.IsReady("rewardedVideo"))
12.         {
13.             var options = new ShowOptions { resultCallback = HandleShowResult };
14.             Advertisement.Show("rewardedVideo", options);
15.         }
16.     }
17.  
18.     private void HandleShowResult(ShowResult result)
19.     {
20.         var health = GameObject.FindGameObjectWithTag("Player").GetComponent<Health>();
21.         switch (result)
22.         {
23.             case ShowResult.Finished:
24.                 Debug.Log("The ad was successfully shown.");
25.                 health.manageHealth(100);
26.                 break;
27.             case ShowResult.Skipped:
28.                 Debug.Log("The ad was skipped before reaching the end.");
29.                 break;
30.             case ShowResult.Failed:
31.                 Debug.LogError("The ad failed to be shown.");
32.                 break;
33.         }
34.     }
35. }

 

Please show your button click code. Also please provide the Debug.Log output