Send from Office 365 Shared Mailbox with Thunderbird

We have a client that wanted to authenticate with SMTP to send out from a shared mailbox. noreply was the name of the shared mailbox. Below is the configuration. User has to have full access and send-as permissions for the mailbox. Hopefully this helps someone trying to accomplish the same thing.


Exchange Configuration:
USER EMAIL: user@domain.com
PASSWORD: password

SHARED MAILBOX: shared@domain.com
SHARED MAILBOX ALIAS: noreply

Settings for IMAP Configuration:
EMAIL ADDRESS: noreply@domain.com (shared mailbox)
IMAP SERVER: outlook.office365.com
SMTP SERVER: smtp.office365.com (port 587)
USERNAME: user@domain.com\noreply (user\shared mailbox alias)
PASSWORD: password (user’s password)
SMTP LOGIN IS DIFFERENT (!)
USERNAME: user@domain.com (users email)
PASSWORD: password (user’s password)

Source for information