Why isn't my AdMob ad unit showing?

Question

Android

The application is published on Google Play, ads are allowed in the settings. In the original version, I try to implement advertising banners, but the server does not send advertising to the application. I tried to use both "native" application and banner identifiers, as well as provided test ones. At the same time, in the new hello world! test banners work, but when you transfer the same code to the application, they no longer work. A big suspicion that the problem is on the side of Google Play, in the settings.
Checked it myself:
Tell me where to look, where to look? The bourgeois Internet dug up many sources, nothing helped.
Here is the error log:

02-24 15:41:23.358 9065-9065/ru.yandex.***.*** I/Ads: Starting ad request.
02-24 15:41:23.358 9065-9065/ru.yandex.***.*** I/Ads: This request is sent from a test device.
02-24 15:41:23.583 9065-9079/ru.yandex.***.*** I/Ads: No fill from ad server.
02-24 15:41:23.583 9065-9065/ru.yandex.***.*** W/Ads: Failed to load ad: 3

Answer 1

Most likely, there are simply no banners that AdMob is ready to show in your application. Even test ads were shown to me N times a day and then turned off.