Sometimes, a connection glitch with your linked account (Facebook, Game Center, Google Play) can cause errors. Try signing out and then back into the relevant service within the game's settings menu, or directly through your device's system settings.
On iOS, the best method is to delete the app entirely and reinstall it to ensure all temporary data is cleared. 3. Free Up Storage Space
The game requires a patch but cannot establish a secure link to the server to download it.