Unity ads not working on real device

Question

In my current Unity program I wanted to implement ads. The ads do work in the Unity editor when I run the game, but when I try to run the ads on my iPhone 7 or iPad Air, there are no ads showing up. Does someone know what I am doing wrong?

using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.Advertisements;

public class GameManager : MonoBehaviour
{

void Start()
{
    Advertisement.Initialize("Appstore-id");
}

bool gameHasEnded = false;

public float restartDelay = 1f;
public float addDelay = 1f;

public GameObject completeLevelUI;

public void CompleteLevel ()
{
    completeLevelUI.SetActive(true);
    Invoke("ShowAdd", addDelay);
}

public void EndGame()
{
    if (gameHasEnded == false)
    {
        gameHasEnded = true;
        Debug.Log("Game over");
        Invoke("Restart", restartDelay);
    }

}

public void ShowAdd()
{

    if (Advertisement.IsReady())
    {
        Advertisement.Show ();
    }
}

void Restart()
{
    SceneManager.LoadScene(SceneManager.GetActiveScene().name);
}

}

Answer 1

I had the same problem and the way I fixed it was a recursive function until the ad was ready. Something like:

IEnumerator ShowAd()
{
    yield return new waitForSeconds(1);
    if (Advertisement.IsReady())
    {
        Advertisement.Show ();
    }
    else { StartCoroutine(ShowAd()); }
}

This way it will call the method until the ad is ready to show. Also, make sure you have test (or debug) mode enabled on Unity Ads Settings.