On April 9, 2024, Microsoft announced a big change in authentication for Outlook add-ins. It’s likely that people don’t realize the kind of change that’s coming. The change removes legacy Exchange authentication methods and replaces them with Nested App Authentication (NAA). Time is running short for developers to upgrade and test their code and Microsoft 365 tenants to get ready for the changeover.

https://office365itpros.com/2024/05/21/outlook-add-in-authentication/

​On April 9, 2024, Microsoft announced a big change in authentication for Outlook add-ins. It’s likely that people don’t realize the kind of change that’s coming. The change removes legacy Exchange authentication methods and replaces them with Nested App Authentication (NAA). Time is running short for developers to upgrade and test their code and Microsoft 365 tenants to get ready for the changeover.
 
https://office365itpros.com/2024/05/21/outlook-add-in-authentication/  Read More

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