One email user receives a 5.1.2 'Invalid destination email system' when attempting to reply to or send to a particular address.
Posted on 2011-04-19
I have a weird problem going in my network. We have an Exchange 2003 SP2 mail server running on a server 2003 platform. We have a mix of Outlook 2007 and Outlook 2010 clients.
One of our users (on a Outlook 2007 client) is receiving the following message when attempting to reply to or send a new email to a specific domain:
Your message did not reach some or all of the intended recipients.
Subject: FW: proof of delivery as requested for PO S82FSAN00001
Sent: 4/19/2011 4:52 PM
The following recipient(s) cannot be reached:
'smorin@Sanjel.com' on 4/19/2011 4:52 PM
The message could not be delivered because the recipient's destination email system is unknown or invalid. Please check the address and try again, or contact your system administrator to verify connectivity to the email system of the recipient.
The funny thing is, no other users in our network, Outlook 2007 or 2010 clients, are affected.
To me, that screams something on the client level, but for the life of me I can't figure out what.
Does anyone have any ideas?