Help from Apple Support
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                            General Help
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                            Troubleshooting by ProblemIf an app unexpectedly quits, doesn't respond to your input, or doesn't perform as expected, do the following, testing after each step: - An app you installed unexpectedly quits, stops responding, or won’t open
- Restart the app: Close the app and open it again.
- Restart your device: Turn the device off and on.
- Update your device software and your apps
- Backup the app's database and Reinstall the app from the App Store: Remember that deleting an app also deletes its data