@apburkha 

Make sure the network adapter on your computer is not set for a static IP but set for DHCP. If you happen to have another computer connect that or maybe a gaming console or TV to see if that is able to get a network connection.

Once the RE220 is connected to your router there is no additional configuration that is needed, you only need to connect a cable to it.

Other things to check would be the LED lights, the 2.4G and 5G should also be lit up.

@apburkha I had the same issue and while I'm not sure this will help... but what I discovered just now is I wasn't able to use the ethernet port in a USB-C hub I have connected to my iPad Pro for some reason.  When I switched over to the Ethernet port of my iMac (with WiFi turned off), I was able to use the Ethernet port no problem.

I happened to upgrade the firmware to v1.1.2 which allowed me to turn off both wireless networks.  While I now have no way of confirming, I assume the Ethernet port was working [before I upgraded the firmware] and for whatever reason, the Ethernet port on the RE220 doesn't play well with the iPad Pro and/or USB-C hubs  *shrug*

I'm just happy the wireless adaptor function works and hope you figure it out too as I nearly gave up!

UPDATE: woke up this morning and my iPadPro works over Ethernet using the RE220 as my WiFi adaptor.  I doubled-checked WiFi on my iPadPro is off so not sure what changed!

At the end of the day, definitely try a different computer and if you still have issues with the Ethernet port on multiple computers, you can try updating the firmware on the RE220 and turning off both WiFi radios to ensure the RE220 is only sending a signal to the Ethernet port. (just keep in mind, you will need to factory reset your RE220 if you absolutely can't communicate with it through Ethernet if you go the same route I did!)