User unknown in virtual mailbox table

[biznizn]

have a virtual server (1and1)
10.4.4 Update #20, last updated at Mar 5, 2012 03:51 AM

created the user ....but I can not retrieve email...it keeps asking for the password
and I get the mail to that user returnd with "User unknown in virtual mailbox table"

using the forums I did
/usr/local/psa/admin/sbin/mchk --with-spam
==> Checking for: mailsrv_conf_init... ok
==> Checking for: mail_handlers_init... ok
==> Checking for: mailsrv_entities_dump... ok
==> Checking for: mail_admin_aliases... ok
==> Checking for: mail_auth_dump... ok
==> Checking for: mailman_lists_dump... ok
==> Checking for: mail_kav8_restore... ok
==> Checking for: mail_responder_restore... ok
==> Checking for: mail_postfix_transport_restore... ok
==> Checking for: mail_spam_restore... ok
==> Checking for: mail_grey_restore... ok
==> Checking for: mail_mailbox_restore... ok
==> Checking for: mail_spf_restore... ok
==> Checking for: mail_dk_restore... ok
==> Checking for: mail_drweb_restore... not exists


I can log into horde with the user name and password, BUT pop keeps rejecting the password

any ideas please...