DCOM hardening - OPC Error in method IConnectionPoint.Advise|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

Hi all

I'm trying to connect my (C++) OPC DA client remotely to Matrikon simulation server when both (client/server) are running on windows servers 2019 with DCOM hardening.

I change the authentication level to RPC_C_AUTHN_LEVEL_PKT_INTEGRITY in CoInitializeSecurity() and set access/security permissions in both windows servers to Everyone and anonymous users. (Of course: firewall is disabled in both server/client) 

My OPC DA client succeeds to connect remotely, browse Matrikon tree, create a group and add items to it - but no updates are coming.

I traced the interface calls and I found out that IConnectionPoint.Advise() method failed (Object exporter specified was not found HRESULT: 0x80070776). Failure in this method prevents from Matrikon server to send updates to my client.

Any suggestion why specifically IConnectionPoint.Advise() method fails? How can I make it succeeds?

Thanks in advance.