the OPCClientDemo.exe can't the server list

[Cpppro]

I have debug find the problem is:
CoCreateInstanceEx(requestedClass, nullptr, serverLocation, &requestedServerInfo, 1, &reqInterface);

return failed.

[duduyoyo]

It looks like you don't have 64-bit proxy dll registered properly.

Alternatively, if you don't want to deal with win32 API like CoCreateInstanceEx() you can try this 64-bit solution. No COM and DCOM is involved, so no DCOM remote call back issue to worry. No OPC C++ component SDK is required either. Besides C++, you can use any preferred static or dynamic languages like Python or JavaScript to access DA data quickly and easily. Cheers!