Having a rather strange email issue...
It seems as though, when sending mail to certain domains, the recipient's mail server is unable to find the recipient's email account. This only seems to happen when we send mail using our TCH mail account (messages sent using different SMTP go through just fine). The first time this happened, a couple of weeks ago, I assumed that it was a problem with the recipient's email server, and contacted the organization's mail admin (still awaiting response).
However, this began happening again with a second recipient's domain.
We are able to send mail to these same addresses with no problems using a different email account. In other words, if I have two email accounts (w/ different SMTP) set up on the same machine, in the same mail client, I am able to successfully send email to the users in question with my non-TCH account, while mail sent from the TCH account always bounces with the same error message.
I was originally inclined to think that it was a problem with the recipient's email server, but since this exact same problem is now ocurring with two different recipient domains, I am beginning to suspect a larger problem.
Is it possible that our TCH domain (homebaseccc.org) or server11 are somehow on a blacklist of some kind? I can think of no reason why this would be the case, but am unsure what else would explain this strange behaviour.
This is beginning to frustrate me to no end! Below are two sample bounce messages (names/accounts have been munged with *** to protect privacy).
Thanks to anyone who can help!