I've been unable to log into the game when I'm on my data connection since at least December 24th. I can still access it on wifi. I have tried powering off my phone, waiting a few minutes & then starting it again, uninstalling and reinstalling the app, and nothing has worked. It still says "Castle Story is an online game and requires internet access. Please double check your connection and try again." But I know I have an internet connection.
My device is a Samsung S9 running Android 8.0.0.