On Mon, Dec 15, 2008 at 10:15:15AM -0600, Sean Carolan wrote: > exmx1 : Dec 14 05:28:39 exmx1 sendmail[31574]: mBDIYhEa031574: to=< > customer at example.com>, delay=00:00:00, xde > lay=00:00:00, mailer=esmtp, pri=41874, relay=mail.example.com., dsn=4.0.0, > stat=Deferred > > Unfortunately there is no reason given for the "Deferred" status such as > "Server unavailable", etc. > > Do you have any ideas how I can begin to troubleshoot this? Hi Sean, Two suggestions, #1 - turn your sendmail logging/debugging setting up as high as it will go for just long enough to capture some of these events. (then turn it back to its previous setting) #2 - try using script and then telnet to capture an SMTP session (Done by hand) with the MTA at the receiving end. This can be a little tricky and requires a good understanding of how SMTP transactions are done so you can emulate it by hand. I would focus on hat the receiving end does when you send it a length that is > 1 MB. Jeff Kinz