In case you have any issues with Facebook linking, please make sure you allowed tracking for our game on your IOS device.
Go to device settings, find Apps -> Ludus -> Allow tracking.
After that you need to reinstall the game so it could ask you to allow tracking when you launch it for the first time (please make sure your account is linked to Apple/Game Center to save your progress)
Open Settings.
General
iPhone Storage
Ludus
Tap Delete to confirm.
Install the game from App Store again.