Hi! I'm having a problem with my ISPConfig3 setup with squirrelmail. I cannot receive any mail! When trying to send, the sender get the following message: This is the mail system at host mydomain. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system <email@example.com>: unknown user: "myusername" Final-Recipient: rfc822; firstname.lastname@example.org Original-Recipient: rfc822;email@example.com Action: failed Status: 5.1.1 Diagnostic-Code: X-Postfix; unknown user: "myusername" I've looked through most squirrelmail and ispconfi3-configs, but I can't find anything remotely related to this issue. Could anyone point me in the right direction? Edit: After some more researching, I found out that if I mail an account NOT setup in ispconfig3, I get this error message instead "MAIL DELIVERY FAILED PERMANENTLY". Something must be right, since it figures out what accounts are actually existing and not? Thanks a million!