Cross-forest or Hybrid Free Busy availability lookups fail in Exchange Server

Note The Hybrid Configuration wizard that's included in the Exchange Management Console in Microsoft Exchange Server 2010 is no longer supported. Therefore, you should no longer use the old Hybrid Configuration wizard. Instead, use the Office 365 Hybrid Configuration wizard that's available at http://aka.ms/HybridWizard. For more information, see Office 365 Hybrid Configuration wizard for Exchange 2010.
Symptoms
Cross-forest or hybrid free/busy information lookups fail in Microsoft Exchange Server. However, standard free/busy information lookups for users in the same forest work as expected.

This issue occurs in the following product versions:
  • Microsoft Exchange Server 2016
  • Microsoft Exchange Server 2013
  • Microsoft Exchange Server 2010 Service Pack 2 (SP2) Update Rollup 1 and later versions
  • Microsoft Exchange Server 2007 Service Pack 3 (SP3) Update Rollup 6 and later versions
  • Microsoft Exchange Online
Cause
This issue occurs if the external URL for Exchange Web Services is not configured in the target forest.
Resolution
Configure the external URL for Exchange Web Services for the target forest. To do this, run the following command in Windows PowerShell for Exchange:
Set-WebServicesVirtualDirectory -identity "server_name\EWS (Default Web Site)" -ExternalURL https://mail.contoso.com/ews/Exchange.asmx

Note In this command, contoso represents the actual domain name.

More information
The versions of Exchange Server that are listed in the "Symptoms" section use the external URL for Exchange Web Services to connect to the target forest. Because the AutoDiscover service cannot return the external URL for Exchange Web Services if Outlook Anywhere is not enabled in the target forest, the cross-forest or hybrid lookup fails.

If either of the following cmdlets returns a value of "$False," the mailbox is not set to allow external connections by using Outlook Anywhere.
  • To verify that the mailbox is set to allow connections by using Outlook Anywhere, run the following cmdlet:
    Get-CASMailbox <mailbox identity> | fl MAPIBlockOutlookRpcHttp
  • For Exchange Server 2016 and Exchange Server 2013, to verify that the mailbox is set to allow external connections by using Outlook Anywhere, run the following cmdlet:
    Get-CASMailbox <mailbox identity> | fl MAPIBlockOutlookExternalConnectivity
References
For more information about the Set-WebServicesVirtualDirectory cmdlet, go to the following Microsoft TechNet website:
Properties

Article ID: 2734791 - Last Review: 07/15/2016 03:44:00 - Revision: 10.0

Exchange Server 2016 Enterprise Edition, Exchange Server 2016 Standard Edition, Microsoft Exchange Server 2013 Enterprise, Microsoft Exchange Server 2013 Standard, Microsoft Exchange Server 2010 Service Pack 2, Microsoft Exchange Server 2007 Service Pack 3, Microsoft Exchange Online

  • kbsurveynew kbtshoot kbprb o365 o365a o365e o365m hybrid o365022013 KB2734791
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