Here is another update:
I’ve checked two regions profound: US and RU.
For US I’ve got “No Ads Available” for your adUnitId once, every other launch and refresh was giving me test banners:
For RU region I was getting test ads every time app requested it.
Android situation is the same, with the mentioned earlier exception that test ads are coming to device without “Test Ad” overlay, so it might be a little confusing.
From this we can conclude that test ads are tied to your region and you may get a no fill situation on specific adUnitIds.
Do I personally think that this is expected behavior? Of course not.
Why is that happening? Only Admob can answer to that and, hopefully, fix it.
Once again, sorry to say that, but Corona have no control over ads fill. Corona’s Admob plugin gives you an easy-to-integrate access to Admob’s SDK and nothing else. I’ve triple checked everything plugin related through internal testing - all working as expected. Test mode is setting correctly and test ads are coming from Admob - the issue is fill of that test ads.
Earlier you’ve wrote that Admob refuses to work with your case and that’s a complete joke of them - you are an Admob’s user, the only difference between you and a native one is ease of integration to your Corona project. My guess is that you’ve asked for help not where you need to - you should write to their support directly, since you are a user, who is not satisfied with the quality of test ads fill and that is the issue they’ve got to help you with, it’s their job.
If you still consider on asking help not from Admob’s support directly - you can ask for help as a native Admob’s user, not mentioning Corona at all, but I highly recommend to solve that issue directly with Admob’s support team.
With that said, I’ll try to find some way to deal with it on our side, but … for now it looks like a completely impossible task to accomplish. Is there anything else I can help you with?