As per the other thread returned in a forum search, the following command made it work, because for each local alias, i.e. in /etc/alias, you need to add the domain to:
Originally Posted by ghenry
So firstname.lastname@example.org will be sent to RT, but email@example.com won't as it's not in above.
mail:~# su - zimbra
mail:~$ zmprov mcf zimbraMtaMyDestination "localhost suretecsystems.com"
However, postfix gives this warning:
Should I care?
ug 10 21:32:41 mail postfix/trivial-rewrite: warning: do not list domain suretecsystems.com in BOTH mydestination and virtual_mailbox_domains