No ad config in release mode

Question

I'm struggling with this problem. I'm using flutter with "native_admob_flutter" to provide the ads since the oficial google widget has several performance drawback. I configured as it says. In debug mode everything just works fine but when install the release version at my cellphone it shows the error "#3 no ad config". I didn't publish the app on play store yet. After some research i read that problem could be that hasn't any ads to show, but it shows in debug mode.