cowellja Connect to the internet without the DC and make sure the internet connection is working.
With the computer on, and DC off, remove the ethernet cable from the computer, plug it to the DC and the computer , turn DC on and wait for a bit.
Check to see if you get a connection. If not, see if you can get into the dashboard.
If that does not work, maybe it is an issue with the network security, or even because of a vLan... I cant try it on my side right now, but when I have the time, I will try that setup in my end and see if it works.