I've been using Thunderbird for a very long time now but I've never experienced this kind of problem: I have few outlook.com accounts set up and looks like I can't send emails from outlook.com using Thunderbird. To send a new email or respond to my emails I have to manually log in to my outlook website account or use my phone (Android). Every time I try to send or respond to email the Thunderbird I get these messages (included in the attachments): no connection to the server or it keeps asking me to put my password even though passwords has not changed. There seem to be no problem with receiving emails.