Sometimes Facebook Messenger keeps closing is the reseult of the shortage of Storage in your cell phone. First of all, go to Settings, and then,Storage, to check the free spece of the Storage. If it is insuffient, you’d better delete some spare apllications, duplicate images or insignificant photos/videos to release the internal memory.
https://www.fonepaw.com/facebook/facebook-messenger-crashing-fix.html

