I am having the same issue with my mail client from my xp machine. Outlook and Opera are not able to log onto and retrieve my email but I can log onto the webmail.
I tried updating the server names in outlook, no change.
When this happened yesterday I reset my password to a new Strong password and it worked.
Today the same symptom, webmail works with my username and password but my email clients do not.
Does anyone have an explanation from Cox? I would hate to have to change my password everyday just to use my email clients.