[Mailman-Users] User unknown error on gentoo

[Alexander]

Without including my domain explicitly under mydestination all virtual 
accounts work successfully, however mailman reports user unknown

Results in mailman list user unknown error
mydomain = XXX.com
mydestination = $myhostname, localhost.$mydomain, localhost

As suggested here 
(https://forums.gentoo.org/viewtopic-t-134833-start-0.html) I added the 
domain explicitly
mydomain = XXX.com
mydestination = $myhostname, localhost.$mydomain, localhost, XXX.com

Now mailman works, but all virtual users are rejected with unknown user

Any suggestion on how to support both vitual users and mailman lists.

So far I have included the following settings and verified the content 
of hte alias databases is correct:

alias_database = hash:/etc/mail/aliases, hash:/var/lib/mailman/data/aliases
alias_maps = hash:/etc/mail/aliases, hash:/var/lib/mailman/data/aliases
virtual_alias_maps = pgsql:/etc/postfix/pgsql_virtual_alias_maps.cf, 
hash:/var/lib/mailman/data/virtual-mailman

Thanks in advance