This is wierd, because email works. For some reason, the links to get to email are broken/missing.
If you type in connect.xfinity.com you should be able to get to your email. It works for me, let me know if it works for you.
To reiterate, forget the links and type this into your address bar:
Hello All -- We are currently experiencing an issue with our email platform. Our engineering team is aware of this and are working on a fix. We should have this issue resolved shortly.