KepServer OPC DA CLient failed to establish callback

[WB_10698363]

Hello,
I have two PCs communicating over OPC DA protocol. One is OPC Server, while second one is OPC Client. On OPC Client I am using KepServer OPC DA Client. I configured DCOM setting according to this page: https://www.softwaretoolbox.com/dcom/html/dcom_for_windows_7-_10-_-_server_2008r2.html . I have latest Windows patches installed which requires from me to use the "Default Authentication Level set to “Packet Integrity” .
The problem is that when I try to connect to OPC DA server, KepServer is showing an error that OPC Client failed to establish callback from OPC Server. When i open Windows System Logs I see error "The server-side authentication level policy does not allow the user MCSB\BHAdmin from address 172.16.3.44 to activate DCOM server. Please raise the activation authentication level at least to RPC_C_AUTHN_LEVEL_PKT_INTEGRITY in client application." That leads me tu guess that I need to change configuration of OPC Client of KepServer, to Packet Integrity. Does anyone know how to do it?
Could You please try to troubleshoot this issue? What might be the cause? Firewall on both PCs is turned off, same user exists on two machines. Packet Integrity as authentication method is chosen on OPC Server. OPC Server is running on Windows 7, while Client on Windows Server 2019
Best regards,
Wojciech

[cmorehead · Accepted solution]

@WB_10698363 ,

Please take a look at the Kepware knowledge base article in the following link:

Article - CS350729 - Unable to establish OPC DA communication after installing Microsoft DCOM Hardening patches (CVE-2021-26414) with PTC Kepware Products

If the article does not resolve the issue, I recommend opening a support ticket with the Kepware team for further troubleshooting. Here is a link to the login page where a support ticket can be opened:

Log In | My Kepware

Thanks,

*Chris