I've one app (ISS Detector), that doesn't send any push notifications for month. The notifications for this app are enabled in the settings and in the app itself. On other devices, the app sends normal push notifications (e.g. for ISS flight passing). Are there any other hidden places, where the push notification settings are set and where may be this special app is somehow disabled?
I'm using Nova Launcher, but no Autostart app and have a none-rooted device (Samsung S7) with Android 8.0.0 Oreo.