webmail show wrong email

CentOS 5.8 Virtualmin 3.98 GPL

So using the webmail @ port 20000, I have users in the same domain (with the same passwords) that see the wrong inbox.

That is, when "karen" logs in, with her full email address, she doesn't see her email. She sees "John's" inbox, and "jim's" sent items.

I have roundcube installed for all domains, with SSL, and it shows the email perfectly fine.

Excusing the fact that the users have the same passwords, and can use roundcube just fine (but still want usermin webmail), what's the dealio?

Any idea what the problem could be? I ran the domain validation and permissions fixups, with no change in status.

If you need more info, please let me know.

Thanks,

Gary