- Quit AirPort Utility if it's open.
- Click the Apple () menu and choose System Preferences. Then click iCloud.
- Sign in to iCloud with your Apple ID and password.
- Once you've logged in to your iCloud account you should be able to open AirPort Utility and set up Back to My Mac.
Airport Utility says your Apple ID or password is wrong after enabling Two-Step Verification
“An Apple ID or password is incorrect or couldn’t be authenticated. Enter the correct AppleID and password and try again.”
This happens even if you've entered the correct Apple ID and password.