In the logs it shows that cox has one of my providers blocked, access denied by policy. I contacted cox on the phone and I get an unknown number lol I emailed the support line but no go. So how do I get off the block or attempt a delist?
Things to start off with:
1. Make sure your outgoing mail server IP address has a valid reverse DNS entry.
2. Make sure your outgoing mail server isn't an open relay (http://www.abuse.net/relay.html to check)
3. Make sure your outgoing mail server IP address isn't on any of the global block lists (http://www.mxtoolbox.com/blacklists.aspx to check).
4. Make sure you have SPF and Domainkeys set up (this may or may not be 100% necessary but good to have anyway).
There are probably other tips but those are the ones that come to my mind.