I have a Note4 and my Facebook icon/sound notifications have suddenly stopped, why?

[Ruth Elaschuk]

I have a Note4 and my Facebook icon/sound notifications have suddenly stopped

I used to get sound notifications and an icon that appeared at the left top hand corner of my phone from my Facebook groups, but suddenly they stopped working.
I've checked all my settings on my Facebook app, shut my phone off, taken the battery out but still nothing....very frustrated at this point. Short of resetting my phone, is there anything I can do? I get sound and icon notifications from messenger and all other sounds are working except from Facebook.....HELP