Go to settings
Go to the facebook backup option
Select Login
It should report that you have been logged out of another device.
All your events appear again as they should.
(This got deleted as a thread once already with no explanation. I don’t know why anyone would have a problem with this fix)
This only works I assume if you already had facebook backup (as I did). I assume at some point in the server craziness your account got flagged as being on multiple devices and it just won’t let you participate.