My notifications for certain apps are not working how do I fix this?

Hello Emsiphone512,

Be sure to check in Settings > Notifications > Select the app, and ensure that notifications are enabled for the app(s) in question, and that the desired alert style is enabled still.

Is this happening with Apple-developed apps and third-party apps, or does it seem to affect only third-party apps or only Apple apps?

Be sure to check for any available updates for the apps in question, as well as for iOS itself. This ensures the latest improvements have been applied: Update your iPhone or iPad

1. Back up your device using iCloud or your computer.

2. Plug your device into power and connect to the internet with Wi-Fi.

3. Go to Settings > General, then tap Software Update.

4. If you see more than one software update option available, choose the one that you want to install.

5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.

Also check to see Background App Refresh is enabled at Settings > General > Background App Refresh > Select the app in question.

It may also help to give the device a quick refresh via a standard restart: Restart your iPhone

Cheers.