Most likely, you're getting this issue if you've purchased an InvizBox Go from the Kickstarter campaign or pre-ordered it and you're only getting to the setup now. (Thank you for you support, you're almost there!)
If you are running a firmware older than 1.1.6 (you can see the firmware version on the Status page once logged in after completing the wizard), then your VPN is not going to work. This is because the certificate delivered in those versions expired on the 10th January 2017.
The solution to this problem is to flash the latest firmware: Find the flashing instructions here