setfmode() | ERROR: Unknown user

[jlawrence]

After upgrading from vhcs I found that all my domains were all 'Account status not ok'.
Trying to change the account status returns setfmode() | ERROR: Unknown user (username)
This is the same on every single account with only the vuxxxx username changing.
I've enabled debug but still can't see any reason why the system thinks it's an unknown user.
All the directories are setup correctly.
If there any obvious way to find out where it thinks the user is unknown.