MC527925 Exchange Online, SharePoint Development Services
From Microsoft Corporation
Technical Bulletin MC527925 · Published Mar 15, 2023
Message Summary
Over the coming weeks, we’re going to turn off basic authentication for the Outlook Service protocol in Exchange Online. This is the protocol used only by the native Email and Calendar app, part of Windows 10 and 11.
When this will happen:
As we communicated last year in blog posts and via Message Center, we turned off basic authentication in our worldwide multi-tenant service from October 1, 2022. This protocol is one of the last changes we will make to complete this effort.
We are not changing any settings or turning off SMTP AUTH.
What should I do to prepare for this change?}
There are a very small number of users using basic auth with the native mail and calendar app, and this change will prevent them from using that app with their mailbox unless they change their authentication settings.
If any user sees an authentication prompt, they will need to update their settings. The easiest way to resolve the issue is to remove and add back the account to the app.
If you want to proactively check to see if you have impacted users, you can use the Azure AD sign in reports, filtering for Universal Outlook as the client app.
If you want to know more about the retirement of basic authentication in Exchange Online you can read more in the link below.
