Topic: error sender unknown user account
I have installed Iredmail 0.6.1, When I send a message I have a returned error:
This is the mail system at host mail.mail.org.
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>: host mail.org.[XX.XX.XX.XX] said: 573
firstname.lastname@example.org unknown user account (in reply to MAIL FROM command)