The No Longer Shared Bug has been Patched in iOS
Tuesday 26th of May, Cupertino stated the bug in Family Sharing that caused apps not to open has been fixed. The bug would cause your iPhone, iPad, or iPod to show a message stating: "This app is no longer shared with you", and requesting that you purchase the app yourself from the App Store. This issue was reportedly affecting users who had previously shared apps through their Family Sharing plan.