That is a site login issue with the email server and if the setting is wrong Thunderbird will not connect. That settings comes from the email site your using and they are the one that can give you the correct settings to connect. So you need to contact them for the correct Thunderbird settings to connect with the email server. Remember Thunderbird connects and send email through that email server not from Thunderbird itself. Also this part is for the Firefox browser help section if you need thunderbird help you should post to the Thunderbird Forum to get users that know more to help there as well.