EAS Proxy PowerShell mode - unable to connect to Exchange 2019 / for unmanaged devices

Hi Together,

to deny access to unmanaged devices we need to change the EAS proxy to Powershell. This article describes how to setup: Set up email access control through PowerShell - Sophos Mobile

There are only a few steps to connect. The EAS Proxy wizard finished the steps with success, where he tests the PowerShell Connection to the Exchange-Server and everything looks fne.

After starting the service the errorlog shows that the EAS Proxy can't connect to Exchange Server anymore.

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2022-12-28 10:51:10.601 [Timer-2] INFO PowershellEASProxyInstance_exch03.xyz.local - Starting Office 365 Task
2022-12-28 10:51:14.622 [Timer-2] ERROR PowerShell_exch03.xyz.local - Error executing Login command: New-PSSession : [exch03.xyz.local] Beim Verarbeiten von Daten vom Remoteserver "exch03.xyz.local" ist folgender Fehler aufgetreten: [ClientAccessServer=EXCH03,BackEndServer=exch03.xyz.local,RequestId=611df702-736f-407b-b26d-08a57df0d7ac,TimeStamp=28.12.2022 09:51:13] [FailureCategory=WSMan-Others] Der WS-Verwaltungsdienst kann die Anforderung nicht verarbeiten. Vorg„nge mit mehreren Meldungen des Clients werden nicht unterst?tzt. Weitere Informationen finden Sie im Hilfethema "about_Remote_Troubleshooting".In Zeile:1 Zeichen:12+ $session = New-PSSession -ConfigurationName Microsoft.Exchange -Conne ...+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : OpenError: (System.Manageme....RemoteRunspace:RemoteRunspace) [New-PSSession], PSRemotin gTransportException + FullyQualifiedErrorId : -2144108529,PSSessionOpenFailedImport-PSSession : Das Argument f?r den Parameter "Session" kann nicht ?berpr?ft werden. Das Argument ist NULL. Geben Sie einen g?ltigen Wert f?r das Argument an, und f?hren Sie den Befehl erneut aus.In Zeile:1 Zeichen:18+ Import-PSSession $session+ ~~~~~~~~ + CategoryInfo : InvalidData: (:) [Import-PSSession], ParameterBindingValidationException + FullyQualifiedErrorId : ParameterArgumentValidationError,Microsoft.PowerShell.Commands.ImportPSSessionCommand
2022-12-28 10:51:14.622 [Timer-2] ERROR PowershellEASProxyInstance_exch03.xyz.local - The login via Powershell failed. Please ensure the following: This machine is able to connect to the specified host. The proxy settings are setup correctly. The host certificate is trusted. The credentials of the service user are correct.
2022-12-28 10:51:14.622 [Timer-2] ERROR PowershellEASProxyInstance_exch03.xyz.local - Office 365 Task failed Error executing command
2022-12-28 10:51:16.101 [Timer-0] INFO com.sophos.mobilecontrol.easproxy.server.EASProxyService - Memory statistics: free: 37.29 MB, max: 1024.00 MB, total: 77.00 MB
2022-12-28 10:56:16.117 [Timer-0] INFO com.sophos.mobilecontrol.easproxy.server.EASProxyService - Memory statistics: free: 37.29 MB, max: 1024.00 MB, total: 77.00 MB

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Things we did:

a) Check the Internet Proxy settings: disbaled
b) Connect to the Exchange Server over the Powershell Console with credentials set in the wizard: succes
c) Install a fresh Windows Server 2022 with the current EAS Proxy Setup: same result
d) Install a fresh Exchange Server 2019: same result

Which we have noticed but for which we have not found any further evidence. In the article (Set up email access control through PowerShell - Sophos Mobile) is the Exchange 2019 not listed. But all other current Exchange Server - is it a problem with Exchange 2019? 

If someone had another idea that would be great.

Best Regards and all a happy new year,
Jochen

Added TAGs
[edited by: Gladys at 8:33 AM (GMT -8) on 30 Dec 2022]