Sorry, wish I had a better answer for you. Cox outsourced their email to 3rd party EasyDNS. They are a decent DNS and email provider, the problem is what Cox paid and what specs their shared servers allow. 5000 messages a day seems to be a bottleneck, so it's probably around that, with limited red flagging. All the spam they used to handle in house, they(Atlanta) now have to pay someone to pipe it to the EasyDNS servers in Texas. Long story short, it just doesn't work well, and Cox probably won't pay to make it better. Not enough profit in email to increase performance. Expect a 5$ "Easy Email" push as Cox tries to increase revenue gain.