So I went and looked at that same URL. I have TB 45.8.0, and unfortunately I have no Tools -> Account Settings, so I can't proceed further.
Sorry, forgot about the stupid hamburger menu. Right click on the grey area just below the title bar and choose menu bar.
Update: Clicked on email. Clicked on Skip this and use my existing email. Entered name (wasn't sure if this was userid), email address and password. I won't go. Either the servers are wrong or I'm wondering if this will work at all. I have 2 step verification where after entering my password it sens a text to my phone where then I put that code in which finally then loads my email. Maybe TB doesn't support that?
Jordan
Hmm, it could, there's a browser in there as well and it tries something similar when I attempt to use Oauth2 authentication, which unluckily is broken. The question is how.
Can you go into Account Settings, look at the Server Settings for your account and report what the Authentication Method is?
I'll do some research but you might have to use something like an app password bypassing the 2factor authentication.
Must be other Comcast users here, maybe they'll chime in.