I'm trying to do a lab that requires access to https://sandboxapicdc.cisco.com but keep getting 504 Gateway Time-out. I have tried multiple browsers.

I am trying to get to https://sandbox-nxos-1.cisco.com/visore.html to get some hands on practice with the NX-OS API REST. I've tried FireFox and Chrome, same results. I am pretty sure that the URL worked fine 2 days ago when I was working with the AP...