setting up comcast email in mail on mac

I'm having the same issue...when I attempt to set up the Comcast.net email in macOS Mail app, i get the msg "unable to verify name or password".

After reading this post (and an older post on the same issue), I went to the two articles suggested and saw:

• Sign in to Xfinity Email using your Xfinity ID and password.
• In the top-right corner, click the Gear icon, then select Settings.
• Click Security.
• Uncheck the box under Third Party Access Security to prevent third-party programs access to your Xfinity Email, or check the box to allow access.

Actually, the box says to check it IF YOU WANT THIRD PARTY ACCESS. The box is not checked so I checked it (because I want third party access). here is a screenshot.

Something is not right. Is this an issue with Xfinity not communicating with the new updates in macOS? BTW, I was discussing this with my neighbor and she said she had not been able to get her comcast emails on her macOS Mail app for weeks but her iphone mail app works ok.