0xC0040002 A duplicate parameter was passed where one is not allowed. |Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

I can able to access the OPC server items when I install the OPC Client on the same machine where the OPC server is available.

I'm facing this error when I try to access the OPC server from the Remote Client PC.

Communication from the OPC Server to the OPC Client is through the OPC Tunnel. 

Should I look for the dependent DLLs in the Client's PC? 

Hi Randy, 

I was able to resolve the issue. The OPC tunnel service was running with the user with no privilege and I can access the OPC Server from a remote workstation. 

I have 2 OPC Clients. one of them is OPCWatchit where I can access the OPC Server. 

On the other OPC client which is called Mirror Client (Emerson), I'm facing this error "Unable to obtain IOPASyncIO from server"

What does this error say?

Thanks Randy, I'm contacting the vendors.