Apple Mail 11.2 High Sierra / unable to create account for Comcast email

Help please -- I am attempting to set up Comcast email on my Mac Pro.

Mac OS is High Sierra 10.13.3

Apple Mail is version 11.2

Per their support site, I'm using Comcast servers:

incoming: imap.comcast.net

outgoing: smtp.comcast.net

I am receiving error: "unable to verify account name or password"

I am able to access email on Comcast's website. Yes, I am using same username and password.

Any suggestions for a cure are appreciated ..

Thanks!