Free/busy lookups stop working in a cross-premises environment or in an Exchange hybrid deployment

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.

PROBLEM

Free/busy lookups stop working for users in a cross-premises environment or in a hybrid deployment of on-premises Exchange Server and Exchange Online. Additionally, these issues may extend to other features that rely on the Microsoft Federation Gateway.

If you run the Test-FederationTrust cmdlet, you receive an error message that indicates that the Delegation token has validation issues. For example, you receive an error message that resembles the following:
Id : TokenValidation
Type : Error
Message : Failed to validate delegation token.

CAUSE

This issue occurs if the certificate and other metadata information in the Microsoft Federation Gateway or in the on-premises environment become stale or invalid.

SOLUTION

To resolve this issue, refresh the metadata. To do this, run the Get-FederationTrust | Set-FederationTrust –RefreshMetadata command.

Note This command forces the information that's used for the federation trust to become up-to-date. You won't have to re-create organization relationships or sharing policies.

To do this, follow these steps:
  1. Open the Exchange Management Shell on the on-premises Exchange server.
  2. Run the following cmdlet:
    Get-FederationTrust | Set-FederationTrust –RefreshMetadata 

MORE INFORMATION

This issue could affect any environment that uses the Microsoft Federation Gateway. These environments include on-premises organizations that have set up free/busy or sharing policies between their organization and other on-premises organizations or Exchange Online in Office 365.

To run the procedure in the "Solution" section as an automated task to prevent future issues, open a command prompt on the Exchange server, and then run the following command. Doing this updates the federation trust daily.
Schtasks /create /sc Daily /tn FedRefresh /tr "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe 
-version 2.0 -command Add-PSSnapIn Microsoft.Exchange.Management.PowerShell.E2010;
$fedTrust = Get-FederationTrust;Set-FederationTrust -Identity $fedTrust.Name -RefreshMetadata" /ru System

Still need help? Go to Microsoft Community or the Exchange TechNet Forums.
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Article ID: 2928514 - Last Review: Dec 29, 2016 - Revision: 1

Microsoft Exchange Online, Exchange Server 2016 Enterprise Edition, Exchange Server 2016 Standard Edition, Microsoft Exchange Server 2013 Enterprise, Microsoft Exchange Server 2013 Standard Edition, Microsoft Exchange Server 2010 Enterprise, Microsoft Exchange Server 2010 Standard

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