USB→2.5GBe adaptor

[Enquiries]

Hi, I wonder if you can advise why when looking at your screenshots - https://nascompares.com/answer/synology-compatible-usb-2-5gbit-ethernet-adapter/ - my exact same 'Plugable' device is not seen? I've tried it in both the front and rear USB ports, but nothing. The device does work, as I've put it into a USB slot in the PC and a Laptop and it does connect. I'm hoping that you can tell me what I'm doing wrong before I return it. btw, my 920+ is on DSM 7.1, whereas this screenshot shows DSM 6.2
Many thanks
David