Connecting MyBookLive to PC offline

I am trying to connect MyBookLive to my PC (Windows 10) without a wired internet connection (I have also WiFi dongle in my PC).
When my pc is connected to the internet via Ethernet, everything works. After disconnection of the Ethernet, it works for a while (during a night) and then disconnecting.
I connected MyBookLive via router and then to the PC. I can see SSDP request on my network card (with WireShark), but they are not responded. I have Static IP for MyBookLive. Tried to reach it with ping, and there is no response.
Any ideas? (I have Antivirus Mcaffee, it seems that it isn’t blocking that)
Maybe my network card is not active when I am connected to the internet via WiFi dongle… But it is strange and I see that my network card is connected (so it seems to be active and working properly).

Ok. I think I’ve solved that by removing the “allow your system to turn off this device” flag in Ethernet Network Adapter device manager… Let’s wait another night and will see…

Ok, it not really worked :frowning: