I have set up an E2003 server (SP1) on top of W2003 (SP1).
When I use a third party POP3 connector to retrieve email from the Internet I get an error saying that Exchange has terminated the connection after the MAIL FROM and quoting error 421 4.1.0.
A quick trawl on the Internet identifies a couple of articles referring to a bug in E2003. The explanation on how to fix refers to Sender and Recipient filtering which on my config are both off, and malformed emails ?!?!
I have checked (and rechecked) the settings in the SMTPvs and restarted the server after every change.
Any ideas on where I start looking to track this problem down?