How to fix iPhone Facebook Messenger notification not working

Top 5 Ways to Fix Facebook Messenger Not Working on iPhone...

Facebook messenger notifications not working - Android Forums at...

Why is my iPhone 6 Facebook Messenger notification sound not...

How do I turn Messenger notifications on and off? | Facebook

Clues to fix iPhone/iPad Facebook Messenger Notifications Not...

No notification for Facebook messenger - YouTube

facebook push notifications are not working on my iPhone 4S all of...