Question Interstitial ads not working on Android devices with Unity Ads SDK 4.4.2

Ever since I was forced by the Play Store to use Unity Ads SDK versions above 4.0.1, interstitial ads have stopped working on Android devices. Banners seem to work fine but interstitial (video) ads just don't work AT ALL. Interstitial ads work perfectly on iOS devices, so the code isn't an issue.

This is my initialization code:

Code (CSharp):

1. void Awake(){
2.     Advertisement.AddListener(this);
3.     if(Application.platform == RuntimePlatform.IPhonePlayer){
4.     Advertisement.Initialize("5179895", false);
5.     }else{
6.     Advertisement.Initialize("5179894", false);
7.     }
8.     }

I even used a differently named placementID for each platform. I just can't understand what's going on here; any help would be incredible!