iPad app will not open

The app on my iPad will not open. I played yesterday morning for probably 20 minutes then a couple of hours later, the app will not open at all. It goes to the game opening screen and a few seconds later it closes itself and returns to my iPad screen. I’ve restarted my iPad, updated software, and restarted app but nothing will work. There isn’t an update in the App Store for the game so not sure what else to do?