What happens if you run the phone in safe mode? If notifications work that would mean that the problem is one of the apps you've installed (which safe mode disables), in which case it's then a matter of identifying which.

 

I don't know because I've not encountered this before. But it's not a common problem so you can probably exclude big name apps (your Facebook's or whatever). If you have any app that is intended to customise notifications in any way that would be a good place to start. If you have something forwarding notifications to a wearable, or a car app, something that sets a do not disturb mode (possibly including calendar apps?) - I'm just trying to think of things that might want to manage notifications, which would therefore be able to interfere with these for other apps. Certainly anything with the android permission ACCESS_NOTIFICATION_POLICY would be worth trying, but it may not be as simple and obvious as that (btw I used an app called Addons Detector to check what apps have what permissions in order to spot that one - I don't have them all memorised!).

 

Create a Guest account on your android phone log in too Guest account after that switch off your phone and on it back problem solve📱