Mail app help

So i have my mail set up for 2 outgoing servers, one for when im at school and one for when im at home. They have both worked perfectly, up until just recently. My server smtp.west.cox.net has not been working since ive been back. I havent changed a thing with its settings since i created it. Anyone have any idea of what the problem could be?

I did update to 10.6 "GM", but i dont know why that would affect one server and not the other.