endpoints points to the old enterprise server

I migrated Sophos Enterprise Console 4.5.1 to a Windows 2003SP2 32-bit physical server to a 2008 R2 virtual server hosted on Hyper-V R2.

All endpoints appeared on the new server without any errors at the migration, but about a week later some clients started pointing at the old server again.

I uninstalled Sophos AntiVirus, AutoUpdate, Remote Management System and reprotected again. It didn't work.

The following is what I have done so far.

1. Edited all mrinit.conf in the clients manually so that it will point at the new server

2. Copied and pasted cac.pem from another endpoint that points at the new server

3. Copied a value from another endpoint and modified the following keys in endpoints

    HKLM\SOFTWARE\Sophos\Messaging System\cac key

    HKLM\SOFTWARE\Sophos\Messaging System\CertificationIdentiKeys\CertificationIdentityKey key

    HKLM\SOFTWARE\Sophos\Messaging System\Router\ParentAddress key

    HKLM\SOFTWARE\Sophos\Remote Management system\CertificationIdentityKey\ManagedApplication key

    HKLM\SOFTWARE\Sophos\Remote Management system\Management System\CertificationIdentityKey key  

4. Restarted Sophos Message Router Service

After the above procedures, I checked Router log. I saw several entries don’’’’t sound right.

ACE+D::::open failed for TAO_ImR_Client: Error

Unable to find service: ImR_Client_Adapter

type=Certification.CertRequest, no originator cert

It sounds the machines don't have a correct cert???

Is there anybody tell me how I  can fix this???

Thanks!