Exchange Hybrid – Free/Busy not working between OnPrem and Office365

Some time back I got few tickets where users were complaining about free/busy not working between on perm exchange and office365, my issue was resolved after following below mentioned action plan, the issue was with delegation Trust and Token Validation, after I refresh Federation Trust metadata  issue Stand Resolved.

In order to test this: Run the below command on On-Premise Exchange Powershell

Test-FederationTrust -UserIdentity

Id : FederationMetadata
Type : Error
Message : The federation trust doesn't contain the same certificates published by the security token service in its federation metadata.

Id : TokenValidation
Type : Error
Message : Failed to validate delegation token.

To fixed the Error I ran the below Command.

Get-FederationTrust | Set-FederationTrust –RefreshMetadata

This will refresh the Trust metadata and the free/busy issue will be resolved for you.

Re run the below command to cross check if the error are gone now

Test-FederationTrust -UserIdentity

Hopefully errors will be gone like above picture and you should be good J