The site could be temporarily unavailable or too busy. Try again in a few moments.
   If you are unable to load any pages, check your computer’s network connection.
   If your computer or network is protected by a firewall or proxy, make sure that Thunderbird is permitted to access the web.

I am setting up a new computer with Linux Mint and Thunderbird. I got my primary comcast.net account added in and working but when trying to add another account I get the following: Unable to connect The connection was refused when attempting to contact localhost. The site could be temporarily unavailable or too busy. Try again in a few moments. If you are unable to load any pages, check your computer’s network connection. If your computer or network is protected by a firewall or proxy, make sure that Thunderbird is permitted to access the web. Since the first account works, I assume there is no problem with network connection, firewalls, or proxy settings. I have confirmed spellings of username and password. Any ideas?