Adding NEW Email

One would think adding a NEW email address to my Xfinity Account would be straight forward and simple ..... Not SO ...
Following the Xfinity "How TO" link here  - https://www.xfinity.com/support/articles/manage-email-contact-settings - after entering the new E Mail address
@comcast.net I get the error "Error Modal" 99 + times- PIC -  After 40 minutes threw my hands up ... SO SAD  Another reason it's NOT Awesome