By default this driver listens to 127.0.0.1 : 51234. (Port number can be changed in the registry.)
If remote access is needed the host must allow DCOM access: run (WIN+R) DCOMcnfg
Make sure to access and launch allow Local and Remote Access to ALL groups.
Also check Defaults:
*Server plugin might not show in this list. Will only be shown if driver is online.
Also add these Firewall rules:
Port: TCP 135 "DCOM inbound"
- C:\Windows\System32\OPCEnum.exe <OR> C:\Windows\SysWOW64\OPCEnum.exe
- <Qinsy installation folder>\OpcClassicServer.exe