catalina – Issues with Ethernet Cable on Mac Mini 2018

I have seen the other questions about issues with “self-assigned IP address” but wanted to add the following detail in hopes it can help:

When I use the belkin usb h and plug in the usb c entry in the back of the mac, the ethernet cable provides internet.

But when used by itself, the cable does not provide internet at all. This mac is brand new – just got it today – so I am not sure the cable is at fault, or the usb hub.

How can I fix this problem?