If an app on your iPhone or iPad doesn't work as expected, try this.
Force the app to close. Then open the app to see if it works as expected.
Restart your iPhone or restart your iPad. Then open the app to see if it works as expected.
To see if updates are available for the app, open the App Store, tap your profile icon, then scroll down to see if updates are available. If updates aren't available for the app, update the software on your iPhone or iPad.
Delete the app. When you do this, you might lose data that was stored in the app. Then redownload the app. Then check to see if the problem with the app is fixed.
If you found the app on the App Store, contact the app developer.
If you bought the app recently and you no longer want it, you can also request a refund.