I have an Exchange 2003 server that has worked more or less perfectly for literally years.
This week, someone told me a contact they had outside of my company could not email any users at my company. I confirmed this, they are receiving an undeliverable notification of “SMTP Connection Failed.”
I have a Barracuda Spam Filter in place, and it has not filtered (or even seen) any recent emails from the user/domain in question. They were able to email my organization about a month ago, but sometime since then they have been receiving this message. The message is obviously generated from their Exchange server, since it never contacts my Exchange Server. This message occurs to both “new” messages and replies to a message from my domain.
What can I look into to double check that it is not something in my configuration?
EDIT: Any other domain I can get a test from seems fine. I’m almost sure it’s a problem on their end. Any advice I could forward on to their IT dept?
Thanks in Advance!
