Hi,
First of all, have you tried using the Ethernet port of the Diva USB 3 on other devices? If yes, does it work or not as well?
If not, then that concludes that the problem is within the Diva USB 3 device's Ethernet port. If it works on another device, then the issue might really be within your laptop.
If that's the case, we can perform a few steps to fix it. First, we can try disabling USB Selective Suspend in Settings > Display > Power & sleep > Additional power settings > Change plan settings > Change advanced power settings, under 'USB settings', under "USB selective suspend setting' set it as 'Disabled'.
Let me know if it helps.
Regards,