Question Microsoft and the new OAuth2 authentication has screwed up my email

[mennoted]

Since making changes to my Thunderbird email in response to Microsoft's new authentication requirements I haven't been able to send emails on my MSN dot com account. I can receive emails, but can't send. I get an error message:
Login to server outlook.office365.com with user name xxxx@msn.com failed

I am seeing lots of similar inquiries for the same error message but no solutions. None of the "fixes" seem to work for me. I've double and triple checked the settings given on the Mozilla help pages and have tried every suggestion out there with no success. Seems to be an SMTP problem. (?) I have two other email accounts using Thunderbird but using different SMTP servers with no problem. Microsoft and Thunderbird help pages don't help ME. Anybody have a suggestion? This has been going on for weeks.

Windows 10 Thunderbird - 128.1.0esr (64-bit) SMPT server: smtp.office365.com - Port 587 - STARTTLS - OAuth2

Any help greatly appreciated

 

[kerberos_20]

by default smtp authentication is disabled with oauth as its too old and users needs to enable it manualy if their mail app still needs it. virtually every mail app doesnt require smtp
https://learn.microsoft.com/en-us/e...e-online/authenticated-client-smtp-submission

quote from ms website on how to turn smtp auth on, if you wish to do so

• If Authenticated SMTP is enabled for your impacted user (this setting does over ride tenant configuration)

1. Navigate to https://admin.microsoft.com/Adminportal/Home?source=applauncher#/users
2. Select the user you are testing this with.
3. Ensure "Authenticated SMTP" is checked.
   

• Please ensure to uncheck "Turn off SMTP AUTH protocol for your organization" by navigating to https://admin.exchange.microsoft.com/#/settings

• Please validate if security defaults has been disabled in your organization.

• If your authentication policy disables basic authentication for SMTP, clients cannot use the SMTP AUTH protocol even if you enable the settings outlined in this article. For more information, see Disable Basic authentication in Exchange Online.