WSUS 2016 not showing connected computers

I am in the process of replacing my aging Windows Server 2008 servers with new Windows Server 2016 servers. My first and top priority is replacing the WSUS. I have created a new VM on my new 2016 server called (for now) DOMCON02 and created the role for WSUS.

I then put two computers in an OU on the 2008 DC as a test and setup a group policy to have them get their updates from the new DOMCON02. I did a Gpupdate on everything and then did a GPresult to confirm my test computer is looking at the new DOMCON02 as its WSUS server.

However, no matter what I seem to do, the WSUS 2016 server doesn't seem to see any computers. I keep getting the message: Your WSUS server currently shows that no computers are registered to receive updates.

The new WSUS server itself seems to be functioning normally. It was able to sync to Windows Update without an issue. It just doesn't see these test computers.

I feel like I'm missing something easy. Why isn't WSUS seeing the two new computers? Is there a delay? Does it take a few hours for it to register the change? I've tried rebooting but it still doesn't see anything. Could it be because the Group Policy and Domain Controller are all still on Windows Server 2008 R2 and the Update service is running 2016?

If screenshots or more information is required, just ask.

Thanks