Nulls Royale Cannot Verify Integrity

I was able to download and play Nulls Royale for about a week. One day I tried getting on it and it said cannot verify the integrity of the app. I tried deleting and reinstalling but to no avail. The app was already trusted in the vpn and device management as well. Does anyone know a fix to this?

I also updated my phone to the latest iOS version as well and redownloaded and still nothing worked.