''<p>duncan24 [[#question-1430639|said]]</p>'' <blockquote>I am trying to add a MS365 mail account to Thunderbird 115.4.2 and keep getting a mail fail message, telling me the login failed, I am receiving mail into this mailbox without issue but sending doesn't work. I get an error message with 3 options, retry, enter a new password or cancel. Enter new password doesn't work. I have set up , as far as I can tell, correctly, the password on the account works for incoming mail. The default smtp server for this mailbox is correct: '''smtp.office.365.com''', port 587, STARTTLS, Oauth2 and my correct mail address for this account. Any thoughts as to what I am not doing? TIA Duncan </blockquote> Is that a typo in the server name? It should be smtp.office365.com.