When going through the wizard to enter Cached Mode, the error: "[ Client Error: SOAPCLIENT_SEND_ERROR ] [ Status Code: 405 ]" is displayed.
The Offline Client does not have the correct URL for the End Point.
Verify that the GPO that was created for the Offline Client has the correct URL set for the Archive Manager Web Service Policy as shown in the Archive Manager Admin Guide. If the URL is incorrect, replace it with the correct URL and force a GPO Update on the client machine.
You can verify this on the local machine by checking the ArchiveWebServiceURL in the registry here: HKEY_CURRENT_USER\Software\Policies\Quest Software\Archive Manager\Client\Offline2