Connection to On-Premise Exchange via EWS using ModernAuth

Question

Hello,

I configured our On-Premise Exchange to work with modern authentication according this https://learn.microsoft.com/en-us/exchange/plan-and-deploy/post-installation-tasks/enable-modern-auth-in-exchange-server-on-premises?view=exchserver-2019

and this https://learn.microsoft.com/en-us/exchange/clients/outlook-on-the-web/ad-fs-claims-based-auth?view=exchserver-2019

Now, all Outlook clients with Windows 11 are able to connect to On-Premise Exchange using Modern Authentication. Also ECP, OWA is working as expected.

My question is related to EWS. How can I configure EWS to work with Modern authentication.

I am able to get the access token from ADFS but when I use it in EWS call I get the error 401 Unauthorized.

Regards,

Emil

Answer 1

As far as I know, EWS with Oauth only works in Exchange Online:

https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/authentication-and-ews-in-exchange

Answer 2

 

Hi @ Emil Pavciak (epavciak)) ,

Yes .As Andy says, OAuth authentication for EWS is only available as part of Microsoft 365 in Exchange Online.

For specific information, please refer to this link: Authenticate an EWS application by using OAuth | Microsoft Learn

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