When I export my app into a .APK file and I install it on my Android phone, the ads work fine and appear. However, after I published my app in Google Play and reinstalled it, the ads don't show up.
What could be the reason!? My ads' Ids are created for a few weeks, they are not new Ids.
I had the same problem, but in the ended up working on some phones, but not on others. One problem that you might have is that the device you tested doesnt have access to internet, so the ads cant be loaded. One other problem might be that there are simply not enough ads to be shown by google admob, so you dont display anything.
