I had the same problem with verizon and cox also trying to set it up. I figured it out on my own. First at the username don't use the @cox.net after your username.They were both telling me to put that in. Now I'm in Arizona so my incoming port I use is 110 and don't check the secure connection or verify certificate at the bottom. My outgoing port is 465 and I have secure connection and verify certificate checked at the bottom.