First, cox.net is no longer Cox's domain. They sold it to yahoo. Cox doesn't have anything to do with email other then delivery the traffic like all the other internet traffic. Been like that for several years. Didn't you have to go through the whole transfer process?
https://www.cox.com/residential/support/coxnet-email-transitioning-to-yahoo.html
That is why CCC(same as CTC?) is probably not able to help as Cox email isn't Cox anymore and CCC/CTC are probably outsourced Plumchoice rep or something. Your best bet will be the Yahoo forum or support, although they upsell support too.
Can you login at Yahoo website? Can you send/receive, both to you and other, there? Are you using Outlook client or website? If client, which? Do other email providers work with that client? What happened 3.5 hours before posting? What was the exact error? My guess is you have to set up a new app password, delete the old one from Outlook, and enter the new one in but can't say for sure without seeing the error/data.
https://help.yahoo.com/kb/SLN15241.html
