If you are seeing a #901 MDL error when trying to enter a tournament, please follow the steps below:
Make sure that your Golf Clash account has been secured to an email address, phone number, Facebook account, Google account or Apple account.
Once secured, uninstall the Golf Clash app from your device.
Reinstall the Golf Clash app and complete the in-game tutorial.
Recover your account via the in-game settings menu by using your chosen security method.
Once you have recovered your account you will have no problems entering the tournament.
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
Golf Clash GAME GUIDE