This error sounds worse than it is. This is caused by a glitch in the TCP stack in Windows. Simply clearing the stack is sufficient to resolve this issue most times. Instructions for doing this are below:
First, I need you to go into your network connections, and locate the connection you connect to the internet with (LAN, wifi). Once you locate it, go into it's properties, and on the General tab, select "IPv4" and go into it's properties. Here, make sure that IP address is set to Obtain Automatically, and apply all the changes.
After this, connect to the VPN again, and go back into network connections; you should see a new connection, which is the VPN tunnel. Do the same thing with it; go into it's properties, find IPv4, go into it's properties, and make sure that IP address is set to automatically obtain, and apply the changes.
At this point, open the Device Manager. In there, expand the Network Adapters list, and choose the adapter you use to connect to the internet (again, LAN or wifi). Right-click on it, and choose Disable, and once it's disabled, right-click again and choose Enable; this should refresh the TCP bindings to it.
Afterwards, go to Start -> Programs -> Accessories, right-click on Command Prompt, and choose Run as Administrator. In the black Command Prompt window, type the following commands, hitting enter after each line:
netsh dump netsh int ip reset log.txt netsh winsock reset ipconfig /flushdns exit
Once the Command Prompt window closes, power down your computer, wait 60 seconds, power it back up, and try your VPN connection again. If your issues persist, please feel free to contact support at any time by submitting a ticket, and we will respond as soon as possible.