Hello,
I have almost exactly problem already discussed here in this old thread:
https://forge.codesys.com/forge/talk/Engineering/thread/03af9426eb/

However, this is quite old and I assume not completely relevant.
In my case, I use v3.5.20 on windows 11, so Winpcap is no longer supported on newer OS.
Also, this hint about adding entry to the .cfg file under ProgramFiles(x86) is also not relevant anymore.
I guess, I need to add entry SysEthernet to this .cfg file:
C:\ProgramData\CODESYS\CODESYSControlWinV3x64...\CODESYSControl.cfg
like this one:

[ComponentManager]
Component.1=CmpTargetVisuStub
Component.2=CmpWebServer
Component.3=CmpWebServerHandlerV3
Component.4=SysCpuMultiCore
Component.5=SysReadWriteLock
Component.6=SysCpuBreakpoints
Component.7=SysPipeWindows
Component.8=SysEthernet

But I'm not sure about Npcap vs WinpCap.

Please, if applicable, update these instructions. I hope it is still possible to