cottfcfan wrote:After you have configured Thunderbird, you have to go back into the server settings, edit/account settings/server settings, and tick SSL for incoming server & then edit the outgoing server and tick TLS, that solved it for me, on Gmail, hope it does for you.
cottfcfan wrote:You could try using your full email address instead of just username.
Check it isn`t case sensitive.
Check your incoming server is correct ie imap/pop.comcast.net.
Other than that i'm as lost as you!