Exchange Web Services not working resulting in issues with enabling the out of office, fetching Free busy calendar information


Windows Authentication was not enabled

Error Message


From Outlook client,

  • Did the Test-EmailAutoconfiguration and it retrieved the EWS URL’s
  • InternalURL was pointing to the Load balancer
  • Added the host file entry on the client machine to point the Exchange EWS URL to the Exchange 2013 server (Start->Run->Drivers->etc->hosts)
  • Tried browsing the EWS URL and got the credential prompt
  • After entering the credentials got the expected page

  • But still got the same error while setting the Out of office and fetching free busy

Checked the below on the server,

  • InternalURL and ExternalURL on the Web Services Virtual Directory using the below command and it was set properly

    Get-WebServicesVirtualDirectory | fl name,internalurl,externalurl

  • Reviewed the logs to see the recent hits from the user ID but couldn’t find any logs in

Http proxy -> EWS logs (%Exchangedrive%\Program Files\Microsoft\Exchange Server\V15\Logging)

IIS logs (%SystemDrive%\inetpub\logs\logfiles\W3SVC1)

  • Now, checked the authentication settings on the EWS VD and found that Windows Authentication was disabled


  • Enabled the Windows authentication using IIS -> Server name -> Sites -> Default Web Site -> EWS -> In the middle pane -> click on “Authentication” -> Windows Authentication -> Right side click on “Enable” (Refer here for more information on default settings on the Exchange Virtual directories)

  • Also, made sure “Providers” are set (Negotiate and NTLM)

  • Did IISReset
  • Restarted the outlook
  • Tried enabling Out of Office and it was set successfully
  • Tried fetching the free busy information and it was working fine as well

Happy learning!! 🙂

By Ashok M

Microsoft Certified Professional, Blogger, Author at, Real world technical contribution via Microsoft Communities (Social Technet/QnA). Extensive knowledge and experience in Messaging (Microsoft Exchange 2003 - 2019) and services including Infrastructure (Windows Server, Active Directory, ADFS, ADCS, File Servers, SCCM), Cloud (Microsoft Azure, Microsoft 365, EMS), Unified Communication (Skype for Business, Video conferencing room systems, Surface Hub), Virtualization (Hyper V), Database (SQL). Have experience in design, implementation, migration & support for various Microsoft infrastructure products across various industry verticals.

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