Hello @johnptd..........I post this message not as an expert; but as one who went through the same misery you are going through. My nightmare lasted three weeks. During that 3 weeks I was angry at every employee who worked for COX. (Follow the discussion here: forums.cox.com/.../suspicious-activity-again-and-again-and-again) even got down to the point where I accused them of intentionally harassing me with emails telling me to change my password......and then finally, I could not send emails. For three weeks I fought and fought and fought with COX people . I swore my machine was clean. I had no "bad files etc" on my laptop.......Heck no, After all, had a MAC.......Well, I downloaded Malwarebytes and Clean My Mac. Then I ran a scan on both.......Wait for it now.....drum roll.....Both .those programs identified two "bad apples" on my laptop.
I eliminated those "apples", changed my password.....................And voila !!!!! problem solved , my email program was up and running.................. Then, I wrote the apologies to COX employees;
Here is what I learned...............COX can fix the problem if the "glitch" in in their system. They can't fix it if the "glitch" is in the users computer.
Again please realize that I send this message only to give you the story of my situation in hopes that it might help you