Meowch! Sorry to hear that, but don't worry. We know what to do.

Please check your Internet connection. It should be perfect for the app to run correctly.
Resetting your WiFi router can fix the issue.
1. Force close the app ( iOS |  Android | Windows )
2. Turn your device off;
3. Turn your device on by holding the power button;
4. Start the game to see if it works again.

Usually, it helps, but please don't hesitate to contact us via the Support button if the issue persists.