See this wiki link: http://wiki.jboss.org/wiki/Wiki.jsp?page=WhyDoesRistrettoOrOtherSimilarMailClientPukeWhenSendingMailToJBMS1.0M3
If you applied this patch before Monday, Oct 17, 2005 19:27PM EST then you should apply it again as the original caused problems with QMail and was unnecessarily verbose.
The problem was that Ristretto does dumb things and is excessively strict when connecting with HELO. It needs to have the method in which it waits for commands and stuff reworked (I have some thoughts on this if anyone is interested).
The problem I created was with QMail wanting "250 " and not "250-" -- the AUTH Methods response was satisfying this, but once it was removed it got mad.
We SHOULD do it the way this patch makes it (and M4 will do it that way) work. It is the most spec compliant and all.
PS I didn't get to M4-pre1 today...was busy working on a secret evil plan for world conquest...