I installed Thunderbird (T-bird), and on the "Set Up Your Existing Email Address" tab, I entered my Xfinity e-mail address/password and clicked on "Continue". T-Bird is able to find the proper configuration in the Mozilla ISP database. I clicked the IMAP radio button and then "Done". That opens a popup window with the heading "Enter credentials for <my-email-address> on imap.comcast.net, but the window never prompts for anything (a prompt for my Xfinity password is what I expected). Instead I just get a message headlined "Unable to connect", with the subtitle "The connection was refused when attempting to contact localhost". This is followed by three suggestions for why that might be the case. I verified that: 1. The Xfinity site is NOT "temporarily unavailable" - I can log into Xfinity directly and see my messages. 2. My computer's network connection is operational since I can load any website at will. 3. I do have Windows firewall enabled, and I suspect that is root of the problem. How can I permit T-Bird to access the web??? Thanks.