Neue Ursache für Hybrid Free Busy Problem seit ungefähr November/Dezember 2025. Probleme bestehen on-prem --> Cloud mit 403: forbidden. Gegenrichtung (Cloud zu on-prem) funktioniert.
Fehlerbild:
Test-OAuthConnectivity -Service EWS -TargetUri https://outlook.office365.com/ews/exchange.asmx -Mailbox testuser@domain.com -verbose | fl
RunspaceId : 1205301b-xc51-451c-a806-a8340a0ced72
Task : Checking EWS API Call Under Oauth
Detail : The configuration was last successfully loaded at 26/11/2025 09:00:24 UTC. This was 7 minutes ago.
The token cache is being cleared because "use cached token" was set to false.
Exchange Outbound Oauth Log:
...
System.Net.WebException: The remote server returned an error: (403) Forbidden. Ursache: Das SettingOverride der neuen Dedicated Hybrid App fehlt. Hinzufügen mit:
New-SettingOverride -Name "EnableExchangeHybrid3PAppFeature" -Component "Global" -Section "ExchangeOnpremAsThirdPartyAppId" -Parameters @("Enabled=true") -Reason "Enable dedicated Exchange hybrid app feature"
Get-ExchangeDiagnosticInfo -Process Microsoft.Exchange.Directory.TopologyService -Component VariantConfiguration -Argument Refresh
Löst das Problem innerhalb von 15min.
