I can’t run the game.

You can’t run the game during server maintenance.
Visit the official community to check if maintenance is ongoing.

If you can’t start the game even when the server is not under maintenance, follow the steps below to troubleshoot.

[How to solve the issue]
1) Delete unnecessary applications or data.
2) Check your OS version and update it to the latest version.
3) Check your network connection status (Wi-Fi or mobile data).
4) Reboot your mobile device.

※ If you keep failing to open the game, delete Defense Derby completely, make sure to connect to a stable network (Wi-Fi or mobile data), and reinstall it.
(Note that your guest account data is not protected if you delete and reinstall the game.)