Sending message to mailing list on domain alias (e.g. firstname.lastname@example.org) fails with one of two errors:
550 sorry, no mailbox here by that name. (#5.7.17)
550 5.1.1 email@example.com: Recipient address rejected: User unknown in virtual alias table
Delivery to same mailing list on its original domain (e.g. firstname.lastname@example.org) works without problems.
The problem is caused by error in product: mailing lists on domain aliases are not properly recognized as valid local addresses by both Postfix and Qmail.
The problem is under investigation by Product Development team and will be fixed in future releases.