How to resolve a corrupted iCloud account
After upgrading a MB air 2014 from 10.9 to 10.13 system prefs will not let me log back into iCloud - constantly rejecting the password. But when I try on iCloud.com it logs in fine.
I made a new blank user on a different machine and when I try to login via system prefs on that one it gives an "unexpected error"
Help ! To me it looks like the issue is with the iCloud account itself.
Anybody know how to unscramble ?