Note:

You'll need to tell thunderbird to add a new account, then click "manual config". Remember to use mst3k@virginia.edu as your mail address when creating the account. The necessary settings are shown in the screenshot below:

That should do it. If you have trouble, you might find these detailed instructions useful:

https://uit.stanford.edu/service/office365/configure/thunderbird

Here are the settings you need in your .pinerc file:

user-domain=virginia.edu
smtp-server=outlook.office365.com/TLS/novalidate-cert/user=mst3k@virginia.edu
inbox-path={outlook.office365.com/SSL/novalidate-cert/user=mst3k@virginia.edu}Inbox
folder-collections=Office365 {outlook.office365.com/SSL/novalidate-cert/user=mst3k@virginia.edu}[]
default-fcc={outlook.office365.com/SSL/novalidate-cert/user=mst3k@virginia.edu}sentmail

Here are the settings for your .muttrc file:

set smtp_url="smtps://mst3k%40virginia.edu@outlook.office365.com/"
set folder="imaps://mst3k%40virginia.edu@outlook.office365.com/"
set spoolfile="+Inbox"
set postponed="+Drafts"
set record="+sentmail"