Facebook notifications not working still after 5 years

It’s been 5 years since everyone was complaining about it and it’s still not fixed. It’s honestly starting to pee me off. It needs to be fixed! Bc when it’s someone’s birthday I don’t even know til I open the app and look at the notification from there. The number of notifications I have for Facebook will show up on the app but I won’t get notifications. I’ve tried everything.