Test Ad not appearing on phone

I’ve made an account for Unity ads and I put the 7 digit code in the service window. When I run the game in my editor it will show the blue test screen no problem.

When I try to build and run the game on my phone though nothing shows up. Am I missing something?

This is the code I am using:

void Start ()

IEnumerator Ad()
        yield return new WaitForSeconds(1);

        if (Advertisement.IsReady())
            yield break;

            Debug.Log("Advertisment is not ready.");   

Any help would be great. I’m really frustrated and am not sure if this is what should be happening in test mode.

Figured out the problem. It wasn’t with Unity or my apk.

I just didn’t have internet turned on on my phone. Once I turned it on it popped up right away