Office 365 email modern authentication will be enabled on Wednesday, June 1, 2022, at noon. This change is not expected to be noticeable by most client applications. Testing has shown that clients will experience one of the following scenarios: 

1. Microsoft Outlook for Windows will continue to use basic authentication until the application is closed. Once reopened, the Outlook client will automatically transition to modern authentication by reusing the cached security credentials. 
2. Other applications connecting to Office 365 email will continue to use basic authentication. These clients will not be affected by this phase of the project. 

This is the next step in our effort to disable basic authentication in our Office 365 environment by August 2022. More information is available in the modern authentication security improvements support article.