Symptoms
While trying to send an email from domain example.com using webmail, one of following errors are shown:
User unknown in virtual alias table
Could not send message to SMTP server. Check you have access to send messages via the server and that all To/CC/BCC addresses are valid
Error: SMTP Server rejected email. Returned:550 5.1.1 admin@example.com: Recipient address rejected: User unknown in virtual mailbox table
Cause
Local Postfix database file /var/spool/postfix/plesk/virtual.db
contains records about domains with mail hosting not from the Plesk server:
# postmap -s /var/spool/postfix/plesk/virtual
admin@example.com admin@localhost.localdomain
Resolution
-
Connect to the Plesk server via SSH.
-
Recreate
/var/spool/postfix/plesk/virtual.db
database by executing this command:# plesk repair mail