Basic Authentication and Exchange Online – February 2021 Update

Hello

I've recently been granted a new Office 365 account with 2 factor authentication and have been trying to set it up with Thunderbird on Windows 10. Have been able to set up IMAP fine including logging in, downloading email and having Thunderbird granted access as a trusted app via the admin. However I'm having problems getting SMTP set up on the specified settings

 smtp.office365.com Port: 587 Encryption method: TLS or STARTTLS

I assume you would prefer we use TLS as it's more secure. You don't say in the guidance. 

In any case being unable to get SMTP configured even using the same account details and password that work for IMAP and having thunderbird approved as a trusted mail client, it still doesn't work. I guess you've done a proprietary hack for Outlook clients.  

I asked why this was the case and on two separate occasions got back a response that amounted to:

"SMTP is a legacy protocol that is blocked by our enhanced security, and will soon be blocked by Microsoft in any event. If you would like more information on this, check out this link:

https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-and-exchange-online-february-2021-update/ba-p/2111904"

With a link to here.

I appreciate it's been a while since I completed my Masters thesis in email protocols, but this sounds rather like <removed by profanity filter />

Can you give me an answer why this appears to work seamlessly with Outlook but not with Open source email clients? 

Is this the intended solution? https://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook-mso_other-msoversion_other/thunderbird-can-not-send-email/b6653b44-8852-4aa9-9153-a165c7be983e

Be as technical as you like, but be accurate. 

thanks

Craig