Recipient address rejected: User unknown in virtual mailbox table

Hey guys,

Weird problem here, I have been sending and receiving emails to one of the domains hosted on my ispconfig setup for about a month now with no problems. I applied the patch over the weekend and everything seemed to work fine.

Tonite however I am not able to send email to any existing accounts on 1 particular domain. I am seeing the following error:

NOQUEUE: reject: RCPT from domain[ip]: 550 5.1.1 <user@domain>: Recipient address rejected: User unknown in virtual mailbox table; from=<user@anotherdomain> to=<user@domain> proto=ESMTP helo=<google server>

The message is being rejected immediately. As a test I created a new user and was able to send mail to that account just fine.

Any suggestions?

 

Can you see the email-adresses in the mysql-table mail_user (for example with phpmyadmin)?

 

Yes, the email addresses exist in the database. I have even compared the table to the backup that was created when ISPConfig was updated. Everything looked the same.