If there is little available storage on your device, you can free i Phone space by transferring photos from i Phone to computer or deleting some data you don't need like apps, photos, podcasts, or videos.
Restarting i Phone or i Pad can troubleshoot may issue like alarm not working in i OS 11, notification or Air Drop not working on i Phone/i Pad if you haven't restart your device for a long time.
As restoring i Phone will cause data loss, you need to make an i Phone backup by using a free i Phone data transfer software which still allows you to import the backup back to your i Phone after restoring.
Ease US Mobi Mover Free is such a tool that can fulfill all your needs to export and import variable i Phone files with one-click, such as contacts, messages, notes, calendars, voice mails, books, Safari bookmarks & history, photos, videos, and audios.
If you're faceting the same problem and don't know how to fix it, you've come to the right place.
This well-designed post will show you 9 common and simple tips to quick fix i OS 11 apps can't download or apps can't update issue on i Phone and i Pad.
Their message was: You have to keep your account in the Swedish region to receive updates.
Note that this applies even to free stuff like Twitter!
So at this point I created another account, to be able to download US apps.
If the Apple ID has no problem, try to sign out and sign in to App Store to settle the issue.
Go to "Settings" tap the Apple ID again and sign in with your Apple ID.