Login through shell and get into user’s /var/spool/mail/ ie. /home/virtual/domain_name/var/spool/mail/
You will get a symlinks for the user Eg: If there is a user test with the primary domain abc.com you get [email protected] —> test –corresponds to mail test#abc.com —> test –corresponds ssh
You need to change the main domain symlink to an additional domain Eg: Suppose the additional domain is “pqr.com” change the links to [email protected] —>test test#pqr.com —>test