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

A technology enthusiast with 9+ years of experience in Planning, Designing, Implementation, Migration and Operations of various Microsoft Infrastructure & Cloud Services. Extensive knowledge of Cloud Computing, Microsoft Messaging & Collaboration, Digital Transformation, IT Services & Emerging technologies. • One of the Authors of the book – “Reimagine Remote Working with Microsoft Teams : A practical guide to increasing your productivity and enhancing collaboration in the remote world” - • Blogger at CloudExchangers - • Microsoft Community Contributor in Microsoft Q&A - • Microsoft Certified Professional in MS Azure, Microsoft365, MS Teams and Skype for Business