Hummingbird The performance scan did not return any results

Hello,

I tried the Hummingbird scan twice on mygreenboard.com which is running on a VPS server. I received this message both times:
"The performance scan didn't return any results. This probably means you're on a local website (which we can't scan) or something went wrong trying to access WPMU DEV. Try again and if this error continues to appear please open a ticket with our support heroes"

Are there settings I need to configure on the server?

Thanks,
Rob