What are the settings for Comcast email in Thunderbird?

Those are decided by the server administrator at Comcast. When folk like you come here and ask about settings, we check one of two things, often both.

The Thunderbird new account wizard database of settings. https://autoconfig.thunderbird.net/v1.1/comcast.net and the providers web site. https://www.xfinity.com/support/articles/email-client-programs-with-xfinity-email

Now I have also looked at the Comcast oAuth implementation bug. https://bugzilla.mozilla.org/show_bug.cgi?id=1844810 where it looks like Comcast popped in to author the necessary changes to Thunderbird to implement oauth for their customers. It also looks to me to be the part that is not working.

The code is here https://searchfox.org/comm-central/source/mailnews/base/src/OAuth2Providers.sys.mjs#19

Try changing your authentication method to normal password in account settings and try that again. I am assuming it is currently set to oauth.

Can you please post your results here as I think the bug needs some followup.

Encountered same problem when entering updated password. Changed the authentication method from oauth to normal password in account settings -- which worked great. Thanks to Matt! (PS donating again to Thunderbird!)

I have tried both authentication methods with no success. No matter which method I try at the point in the Account creation process, where it submits my username to the server I get the following error message:

Access Denied You don't have permission to access "http://login.xfinity.com/login" on this server.

Reference #18.bbc1c917.1728147877.3d46dbbc

https://errors.edgesuite.net/18.bbc1c917.1728147877.3d46dbbc

It just won't work. I called Comcast and they say it is a Thunderbird problem.

I forgot, I can login to my Comcast email just fine on Comcast's website.