Yup I tried reinstalling already but it’s still down. The crashed happened suddenly while I was using it.
Not sure if it’s an iOS thing but it seems there are some complaints on other forums.
Edited:
I managed to resolved this.
What i did was the following,
1) Logout from Facebook app
2) Delete Facebook App
3) Delete Messenger App
4) Install Facebook App
5) Install Messenger App
6) Opened Facebook App and login
7) Opened Messenger App and login
That seems to have solved the problem for me.