I set up Postfix on the VPS. I can send mail using "Usermin" however it will not receive messages. I receive the following error message back from the server:
<firstname.lastname@example.org> (expanded from
<email@example.com>): unknown user: "default-langsystems.net"
Final-Recipient: rfc822; firstname.lastname@example.org
Diagnostic-Code: X-Postfix; unknown user: "default-langsystems.net"
I also cannot connect with Thunderbird. Can anyone point me in the right direction?