Apple mail problems with Cox
I know this has been a past subject talked about... maybe my problem is different. I have 3 Cox webmail accounts, 1 primary and 2 secondary accounts. The primary and one secondary works correctly from Apple mail - All three are accessible properly on Cox browser webmail. I have confirmed(?) with Cox that the account is working properly with username/password on the Cox server.
But from home I cannot log into that ONE account to get mail. I have tried deleting and remaking the account dozens of time. And since webmail, browser mail, works properly on the COX site, they say it's an Apple problem. I have used that account for years and can't figure why it fails now. Mail Doctor say the primary and one secondary is all green. That account is red. Help anyone.
iMac with Retina 5K display, macOS 10.15