First, check that you are able to communicate with the host from your client.
If you get this error while attempting to query a server using
opcserverinfo, or when attempting to add a host in the OPC Data Access Explorer app, the OPC Foundation Core Components have not been installed correctly.
If you are unable to query the server using
opcserverinfo, the most common cause is incorrectly configured local DCOM security settings.
An inability to connect to the OPC server usually indicates that the security model on the server is not allowing you to make an initial connection.
If you are able to connect to the server but cannot create a group, the most common cause is incorrectly configured local DCOM security settings.
If you get this error while attempting to add a group to a connected client object,