Oh, one other change I'm making: there was no default server name set up in iMS POST, and the machine itself doesn't have a FQDN. Therefore, I wonder if the sender's mail server was choking on that. I've now added mail.onebigsite.com in the POST settings as the default machine name for HELO. Previously it would HELO the receiving machine simply as HOST17 (obviously not a FQDN).
> ----- aaa Original Message ----- > There IS an MX record that is exactly that. However, I wonder if the > CNAME record is causing this to be the problem in this sender's case. > I'm dropping the CNAME's and instead making explicit A records to see > if that changes the deal.
