Update (Nov 10, 10:00 UTC): We are still actively working on fixing this issue together with Facebook. Thank you for your patience and understanding.
We are aware that some players are experiencing issues with connecting their game accounts to Facebook.
We are currently investigating this here and will try to get it resolved as soon as we can. We will update this post once we have more information to share.
Please note that your game progress is not saved via your Facebook connection. The way to save, recover, and sync your progress is by signing in to Game Center (on iOS) or Google Play (on Android).
Thank you for your patience, and our apologies for the inconvenience caused by this!