I did notice there were two ways to access the chat. The link I gave you
http://ww2.cox.com/aboutus/arizona/contact-us/residential-local-chat.cox
vs maybe the link that doesn't work?
https://www.cox.com/support/emailchat/chatusenglish.asp
So Im guess something with the recent site re-design and the ww2.cox.com vs www.cox.com. Not sure, but glad I could help.