We're aware that Mac OSX Sierra VPN setup requires an IP address of the server rather than a Servername
IP addresss are likely to change from time to time, so we generally don't publish them, however, to work around this for Sierra, do the following.
1. open a new terminal window
2. Type nslookup and then the servername
nslookup usa1.vanishedvpn.com
3. The ip address will be at the bottom of the response
Non-authoritative answer:
Name: usa1.vanishedvpn.com
Address: 108.61.168.215