google Banner failed to load ad 3
<p>I was using google demo test bannerAd. Until yesterday it was working just fine. Yesterday the banner didn't load anymore, I did not change anything in the code. Reinstaling the demo did not show the banner either.
The InterstitialAd demo still works fine. What could possible cause this problem. 
 I recently upgraded Android Studio and the SDK to the latest version. Could this cause the problem.</p>