Dear colleagues, 

We are reaching out to inform you of an important upcoming change that may impact your ability to send emails using Exchange Online. 

What’s Changing? 

As part of Microsoft’s ongoing efforts to improve email security in Exchange Online, Basic Authentication for SMTP client submission is being permanently retired. Starting March 1, 2026, Microsoft will begin rejecting Basic Auth connections, with full enforcement by April 30, 2026 (revised from the previously announced date of September 2025).   

What This Means for You 

Our monitoring shows that you are currently using Basic Authentication to send emails via SMTP. Please note that after April 2026, this method will no longer be supported. Any service, application or device relying on it will be unable to send email through Microsoft 365. To prevent service disruption, you will need to transition to a more secure authentication method (OAuth, SMTP relay, etc.). 

Please review the official Microsoft announcement for detailed recommendations and available resources related to this change.  

If you have any questions or concerns, please submit a ticket to the Enterprise Service Centre at (https://uoft.me/m365help). 

Kind regards,  

Enterprise Applications & Solutions Integration (EASI)
Information Technology Services, University of Toronto
215 Huron Street, Toronto
Ontario M5S 1A2