[imp] Using IMP with Exim

[James Brown]

All,

I recently changed from Sendmail to Exim (as well as upgrading to 
IMP-3.2.5) and am having some occasional problems with sending emails. 
This is what I see in my exim log:

2004-08-03 23:18:01 1Bs7bc-0000HY-MS ** www at mydomain.com R=dnslookup 
T=remote_smtp: SMTP error from remote mailer after RCPT 
TO:<www at mydomain.com>: host mail.remotedomain.com [212.42.x.xxx]: 550 
unknown user

The message is then frozen and does not get delivered.

I am also seeing this in the headers of the mails which *do* get delivered:

From: me at mydomain.com
To: person at remotedomain.com
Return-path: <www at mydomain.com>
[...]
Sender: World Wide Web Owner <www at mydomain.com>
[...]


I'm sorry if this turns out to be more of an Exim problem than an IMP 
one, but I'd be very grateful if anyone could help me or offer advice.

Many thanks,

James.