I continue to get this error on REPLY emails to one particular domain, yet I can initiate email to that domain w/o a problem. I do not have issues replying to any other domain. I should note the domain in question is using Google to host their domain name.
"Your outgoing (SMTP) mail server has reported an internal error. The server responded 571 5.7.1 Message contains spam or virus, or sender is blocked."
I'm inclined to believe the problem exists within Outlook 2010 or Windows 7 Professional because I am able to initiate replies using webmail.
We do not have this problem on a machine running XP Pro using the exact same port settings.