Another reason why Comcast emails don't work
is that you're using the wrong password or incorrect email address. You can try changing your password, or trying to disable third-party apps. Sometimes, deleting the wrong application or uninstalling it will solve your problem. If the problem still persists, follow the next step. If you have a smartphone, you can try changing the application on your phone to work better.
See also - https://emailspedia.com/cannot-send-receive-emails-with-comcast/