My computer which runs Windows 10 sees my 7" China GPS, but Naviextras will not see it.
The main cause for this issue is compatibility of NaviExtras with your device. I have checked and found a list with compatible devices that NaviExtras Supports. You can browse using the link posted below.
Secondly, in the Device manager, make sure there are no yellow marked items. If there are, it indicates a driver might not be installed.
Compatibility list: https://www.naviextras.com/shop/portal/devicessupport