"Upgrade your Xfinity Gateway – at no additional cost!" link fails

I received an email from "Xfinity <xfinity@emails.xfinity.com>" with the Subject, "Action needed: Replace your internet equipment at no extra cost".  The details in the email sounded good, so I clicked on the link.  The link is [Edited: "Invalid link"]

This URL brought up a sign-on screen, so I signed on.  My browser went back to the link URL, which showed the three larrge dots (I think that's what it was showing, but it went by too fast for me to be certain).  But clearly it was the widely used animation indicating that the website is processing my request.  I've often seen it on xfinity.com.

In perhaps a tenth of a second after that animation, the entire page went blank.  Reloading the page duplicated the behavior.  Trying this out on all three browsers that I use had the same result.  Very annoying, to have my time spent on nothing more than ending up with this "question":  Would you please fix this?