Recently some of my apps have stopped notifying me about messages or any other things. So, I don't receive notifications in time, but then I open an app and see all those messages that were actually received several hours ago without me knowing about it. If that's not about the notification settings (I've checked that one and everything is OK there), what can it be? The notification issue is in Whatsapp, telegram, and sometimes Facebook. Android 9 Thanks for any suggestions!