Thunderbird will receive mail but I cannot send mail. When I try to write a new message the "To" address is coloured red and the Send Icon is greyed-out. When I try to manually set up TB I get the message "Incoming server already exists" and I can get no further. I can send and receive webmail with my server (British Telecom). Copying the BT password into TB doesn't solve the problem. Help, please!