I backed up all my stuff, reset my tablet to factory defaults, and reinstalled all my apps. The game works again. It was a last ditch effort that I don't recommend unless you get as frustrated as I did.
I'm having a similar problem and emailed support say I had already tried disconnecting/reconnecting to fb, reinstalled the game, restarted my tablet, etc. and asked for advice. I received an autoreply telling me to do the things I'd said I'd already tried and referring to the King Care Community. Here I am, and the issue…