* Restart your device. This can clear the memory and fix small glitches.
* Check your phone's available storage. If it's running out of space, you can delete some files to make room for the app.
* Check for a bad app update. Sometimes apps automatically update in the background, and you may have missed the notification.
* Clear the app's cache. You can do this by going to Settings, finding the app that isn't working, and looking for an option called storage.
* Reinstall the app.
* Reset the app's preferences. You can do this by going to Settings, selecting System Settings, and then selecting Reset Options.