Users have been experiencing this issue quite often after updating their iPhone software to iOS 11. This problem may be due to the software or the app by itself. In case it happens only with the app, the best solution to fix this issue is to remove the app so that it doesn’t happen in the future. If the problem is with the software, like one or more apps freeze unexpectedly, then proceed with step 1.
Step 1
Try ‘Force Quit’
First and foremost step before proceeding into fixing it technically is try force-closing the app/apps. When app freezes, tap the home button twice and swipe up the app window to force shut it down. Try launching again. If the issue still persists, proceed to step 2.
Step 2
Try ‘Updating’
Visit the App Store, tap on the 'Updates' tab. Check if there are any available updates for the app that crashes frequently or randomly. If it is available, do update it. You can also opt to update all the installed apps that are yet to be updated by clicking on the 'Update All' tab.
Step 3
Try ‘Deleting and Reinstalling'
If updates are not available and the app freezes once in a while, hold the app icon on the screen for about a couple of seconds. An X symbol appears at the top right corner of every app. 'Delete' the app and 'Download' it at the app store and 'Update' it. Once it is done, try opening it again from the 'Home Screen'.
Step 4
Try ‘Restarting’
Try 'Restarting' device and check if the issue is fixed since restarting clears cache.
Step 5
Contact ‘Developer’
In case the app freezes again and the problem persists, provided the app cannot be updated and had followed step 1 and 2, there is always an option to contact the 'App Developer'. Visit app store, click on 'Customer Reviews' section and tap app support.