Version 10.14.6, MacMini (Late 2012).
Will sporadically send / receive email
I can access comcast and yahoo via their web browsers
I have confirmed, multiple times, the mail profiles have the right passwords
I can access the emails from my iPhone8 v 13.6.1 with the mail app and my MacBook Pro sorry its at work so I can't get OS version
I have looked at the referenced support document and believe I've checked all the steps
I continue to get the exclamation in the triangle alert after downloading messages and go back through the connection doctor