1) Double-check that the VPN IP Address, Username, and password are correct

2) Set the router and firewall settings to allow for PPTP and/or VPN pass-through
TCP Port 1723 and GRE Protocol 47 must be opened/enabled for PPTP VPN connection.

3) For Windows users, go to the VPN Properties, click on the Security tab
and change Type of VPN to Point to Point Tunneling Protocol (PPTP)

4) Check the VPN IP address again.  Make sure you do NOT include "http://" and "/" in the VPN IP address: