[exim] Connection Lost (Barracuda Spam Appliance)

Hi --

I have a fairly vanilla install of Exim(4.66) on a Linux (Centos 4)
The host uses exim as installed from Cpanel (A hostting platform).

I'd like to filter email through an off site spam filter appliance (Barracuda)
When setting up the domain in the barracuda I can test the connection
to the MTA.

I get back a failure...
Error performing SMTP test:
Connected to X.X.X.X:25 session output follows:
220-host3.hardover.com ESMTP Exim 4.66 #1 Sun, 08 Jul 2007 08:44:25 -0400
helo host.domain.name
220-We do not authorize the use of this system to transport unsolicited,



The exim_main_log simply shows this message...
SMTP connection from (host.domain.name) [x.x.x.x]:34636 I=[x.x.x.x]:25 lost

There is nothing to reference int he reject log. This error is
generated very quickly, so I'm guessing its not really a connection
timeout problem.

Any clues on what config changes I might be able to make on the exim
side to make this work or atleast to troubleshoot further?

Thanks
Brad