A colleague sent a message to email@example.com and received the message below. I am not sure if the problem is with our mail server or with theirs. And if the problem is with our mail server then how do I fix it?
From: System Administrator
Sent: April 18, 2006 5:07 PM
Subject: Undeliverable: FW: TUB219
Your message did not reach some or all of the intended recipients.
Subject: FW: TUB219
Sent: 18/04/2006 4:33 PM
The following recipient(s) could not be reached:
firstname.lastname@example.org on 18/04/2006 5:07 PM
You do not have permission to send to this recipient. For assistance, contact your system administrator.
<lab-mail1.laborie.com #4.7.1 smtp;450 4.7.1 <lab-mail1.laborie.com>: Helo command rejected: Host not found>