Having a little trouble setting up an “post by email” address.
I get this error.
I’m sorry to have to inform you that your message could not be
be delivered to one or more recipients. It’s attached below.
For further assistance, please send mail to
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The Postfix program
Final-Recipient: rfc822; email@example.com
Original-Recipient: rfc822; firstname.lastname@example.org
Diagnostic-Code: X-Postfix; unknown user: “m5428841”
Who is “m5428841” and why won’t he let me do what I want?!