When a VPN connection fails, the client program reports an error message typically including a code number. Hundreds of different VPN error codes exist but only certain ones appear in the majority of cases. Many VPN errors require standard network troubleshooting procedures to resolve:
Ensure the computer running the VPN client is connected to the internet (or another wide area network), and that the access to the outside network is working Ensure the VPN client has correct network settings required to work with the target VPN server Temporarily turn off the local network firewall to determine whether it is interfering with VPN communications (some types of VPNs require certain network ports to be kept open)
Below you’ll find some more specific troubleshooting: In some cases, the administrator may need to update MS-CHAP (authentication protocol) support on the VPN server. Any of these three error codes may apply depending on the network infrastructure involved.
