Cannot get iMessanger to work

I received a message to say I’d be logged out of iMessanger due to an error.

when I try logging in it just buffers.

my connection is fine, WiFi only on IPad2020.

All updates are up to date.

i e rebooted and waited 24 hours. Still no luck.

online advice is to go to Settings and turn off messenger. There appears to be no way to do this on my iPad. Besides which, in settings, the log in page is there, but the password box is greyed out.

Help!