There is an issue that happens with iOS from time to time and has for many versions where contact names disappear from the Phone app and you only see the phone numbers. Further, when clicking on a contact a call fails to be placed generally with an error message from the Carrier. You may also notice that your data continues to work and that if you manually type a phone number you can call it. You may also notice that whenever you call from clicking on a contact that you see something about “Dial Assist” on the main screen.

There are two fixes you can try in order to alleviate this, neither of which require a reset. They should be tried in this order.

Fix 1

1. Start the Contacts app
2. Click on the “Groups” link which is likely in the top left corner
3. Ungroup or remove the check marks from all of the selected entries then click “Done”
4. Click “Groups” again and reselect the previous entries then click “Done”
5. Restart your phone

This approach worked for me to restore all functionality.

Fix 2

This won’t fix the core issue but will allow you to click on a contact and call that number. You can disable dial assist and it will then correct call the contact number if it is properly formatted.

1. Click Settings
2. Click Phone
3. Turn off Dial Assist

Although Fix 2 will restore some functionality, Fix 1 is what we’re really hoping works because it will fix the problem AND dial assist will continue working. This was verfied on iOS 12.1.4 where these instructions were created from however the issue has existed for some time over a wide span of iOS versions.