If you have any problems connecting to Facebook, please refer to the following steps below:

1. Logout and go to settings -> Login to your Facebook account.
2. Double check whether the game is allowed in the game, below the "Also these apps to use your account."
3. Open the game and try reconnecting to Facebook.

If the game is not working, download Facebook from either Google or App store. After setting the app, login to the account that you want to connect to the game.

Hope it helps.