I've got problems with my thunderbird. It was working absolutely fine and now all of a sudden it won't send any mail. It's receiving no problem but when I try to send it brings up a box asking me for my btyahoo password, and when I put it in it just brings up the box again. I know the password is right so what's going on? It's a pain having to go into yahoo online to send mails when all my received mail is coming to thunderbird!