I've been having some trouble recently with mail to jackvinson.com bouncing to the senders. If this is happening to you, I'd appreciate your letting me know via jackvinson AT comcast DOT net.
The diagnosis I've been able to do thus far is that my domain has somehow gotten associated with spamming practice. Yippee. When I checked jackvinson.com against the robtex multi-RBL check (as well as others), two of the RBL (realtime blackhole list) servers have me listed. I've been able to automatically remove my domain from one, but they warn that if the practice continues, I will get re-listed.
If you happen to know how to fix this, I'd love to know. I buy service from a hosting provider, so I'm assuming there is something in that setup that is allowing for the spam practice. I'm guessing I'd have to pass along information to my provider.