Error # The RPC server is unavailable.

Hello,

Since yesterday we see for all the servers that we monitor in Application Management (Build No:8501) this error: Error # The RPC server is unavailable.

To our knowledge no changes have been made to the remote servers, or the server running application manager.

We have NO firewall running on all our servers.
The WMI and RPC ports are open.
The RCP and WMI services are running.
The DCOM config on the remote servers is ok.
The remote servers can be pinged/traced.

Attached:
- Screenshot of the error (1)
- Screenshot of the DCOM setup (2)

The Support file (Zip) is uploaded to the FTP server, no idea what the file name is, but its removed from the server.

Could you help to solve this issue? To our knowledge nothing is changed on the servers (maybe an security update of Windows). So it might be something within App Manager. Could you point me in the correct direction and help me solve this?

Thanks in advance!