Comcast is currently working on the problem since it's so widespread. Keep an eye on the following topic for more updates:
Hello, hisbrn. Thanks for reaching out to us on the forums. I apologize to hear you are having issues accessing the My Account app or website. I would like to look into this for you. Can you please send me a PM with your first/last name and user id you are trying to log in with?
To send a private message, please click my name "ComcastMichael" then select "Send a Message" on the right side.
Hello, hisbrn. I have not heard back from you. If you still need assistance, please feel free to start a new thread.