I'm having a major issue.. an outbound user is trying to send mail and it gets rejected with this below: This Message was undeliverable due to the following reason: Your message was not delivered because the destination computer refused to accept it (the error message is reproduced below). This type of error is usually due to a mis-configured account or mail delivery system on the destination computer; however, it could be caused by your message since some mail systems refuse messages with invalid header information, or if they are too large. Your message was rejected by MAIL.windowrock.net for the following reason: 5.7.1 Requested action not taken: message refused The following recipients did not receive this message: -I've ready many blogs about this and it's all the same reasoning. Our system is blocking that email... well were not blocking this email address. Please help. Thanks

why would you think its your server when it clearly states "because the destination computer refused to accept it"? have you contacted the admin of the remote email system? Give a person a fish, they eat for a day. Suggest they internet search and they learn a skill for a lifetime.

Are any of the email addresses involved (From or To) used with a redirect? Some email servers are set to "authenticate" the domain to ensure their is actually a mail server for that domain. I recall having a similar issue - may be the same but I don't remember the specifics. When I sent mail from my work to ny home address, the messages were dropped (might have been the same going the other direction). The problem was that I was using an account with my own domain (e.g. me@mydomain.com) but that domain wasn't being hosted. I had a redirect service that would forward any mail to that account to my email account through my ISP (e.g. me@myisp.com). Well, the email server at my work would see that there was no email server hosting the mydomain.com and would drop the emails. This is to prevent malicious use of email from spamming activities. Michael J