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can't send mail on new personal Outlook.com account

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tbirdUser_t3
tbirdUser_t3

Can get(POP3), but can not send emails to a newly created personal outlook.com account.

the following error occurs when trying to send mail: Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)

all my setting are correct per thunderbird and microsoft: 

  (smtp-mail.outlook.com, port 587,  STARTTLS, OAUTH2, xxxxx@outlook.com)

thunderbird error log file contains the following: . . . mailnews.smtp: S: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]

SmtpClient.sys.mjs:452:17 mailnews.smtp: Command failed: 535 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]; currentAction=_actionAUTH_XOAUTH2 SmtpClient.sys.mjs:578:19 mailnews.smtp: Error during AUTH XOAUTH2, sending empty response . . .


Based on my understanding its seems thunderbird is using SMTP AUTH instead of OAUTH2 as required for newer personal outlook.com accounts. Is my assessment correct? If so, is there a fix?

Can get(POP3), but can not send emails to a newly created personal outlook.com account. the following error occurs when trying to send mail: Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP) all my setting are correct per thunderbird and microsoft: (smtp-mail.outlook.com, port 587, STARTTLS, OAUTH2, xxxxx@outlook.com) thunderbird error log file contains the following: . . . mailnews.smtp: S: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A] SmtpClient.sys.mjs:452:17 mailnews.smtp: Command failed: 535 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]; currentAction=_actionAUTH_XOAUTH2 SmtpClient.sys.mjs:578:19 mailnews.smtp: Error during AUTH XOAUTH2, sending empty response . . . Based on my understanding its seems thunderbird is using SMTP AUTH instead of OAUTH2 as required for newer personal outlook.com accounts. Is my assessment correct? If so, is there a fix?

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