Try restart your phone or wifi, this happens sometimes but a game restart fixes it
Restarted three times. Even offloaded and redownloaded the game.
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Possibly try a WiFi reboot?
Make sure you back up your game data to Facebook. Force stop the game, clear all cache. Uninstall game, reboot phone, redownload and install game.
I use Game Center and physical backups, don’t use Facebook.
Tried that. This has happened before, had to wait it out, missed three days of the login calendar.