Are you saying it can't connect to comcast.net? You might try re-installing the app. I'm able to log into my app. Can you log into your web account with comcast.net?
I pulled up your account & do see some successful app activity. What device are you experiencing this issue on? If possible, can you attach a screenshot of the screen you are directed to that is asking you to log in? Screenshots can be added to your reply by clicking on the Camera/Photos icon above the reply text box.