VPN Error Codes & Solutions
VPN Error Code: 800
Error Description: The remote connection was not made because the attempted VPN tunnels failed. The VPN server might be unreachable. If this connection is attempting to use an L2TP/IPsec tunnel, the security parameters required for IPsec negotiation might not be configured properly.
Possible Cause: This error comes when the VPN tunnel type is ‘Automatic’ and the connection establishment fails for all the VPN tunnels.
Solution: If you know which tunnel should actually be used for your deployment, try to set the ‘Type of VPN’ to that particular tunnel type on the VPN client side. [This can be set by clicking the ‘Network Connections’ icon on the bottom right of the task bar, Select your Connection, Right Click -> Properties -> Securities Tab -> Under ‘Type of VPN’ select the interested VPN tunnel type]
VPN Error Code: 806
Error Description: 806: The VPN connection between your computer and the VPN server could not be completed. The most common cause for this failure is that at least one Internet device (for example, a firewall or a router) between your computer and the VPN server is not configured to allow Generic Routing Encapsulation (GRE) protocol packets. If the problem persists, contact your network administrator or Internet Service Provider.
Possible Cause: PPTP uses GRE (Generic Route Encapsulation) protocol to encapsulate the VPN payload in a secure manner.This error generally comes when some firewall in path between client and server blocks GRE Protocol (i.e. IP protocol number 47).
Solution: Allow both outgoing and incoming Protocol 47 (GRE) on any in between firewalls. If that is not possible, deploy SSTP based VPN tunnel on both VPN server and VPN client – that allows VPN connection across firewalls, web proxies and NAT.
VPN Error Code: 789, 835
789: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.
835: The L2TP connection attempt failed because the security layer could not authenticate the remote computer. This could be because one or more fields of the certificate presented by the remote server could not be validated as belonging to the target destination.
Possible Causes: This is a generic error which is thrown when the IPSec negotiation fails for L2TP/IPSec connections.
Solution: In case Pre Shared Key (PSK) is used, make sure the same PSK is configured on the client and the VPN server machine.
VPN Error Code: 691
Error Description: 691: The remote connection was denied because the user name and password combination you provided is not recognized, or the selected authentication protocol is not permitted on the remote access server.
Possible Cause: This error is given when the authentication phase erred out because of wrong credentials being passed.
a> Make sure correct username and password is typed.
b> Make sure ‘Caps Lock’ is not turned ON while typing credentials.
c>This error can also happen when an IAPS account has expired.
VPN Error Code: 809
Error Description: 809: The network connection between your computer and the VPN server could not be established because the remote server is not responding. This could be because one of the network devices (e.g, firewalls, NAT, routers, etc) between your computer and the remote server is not configured to allow VPN connections.
Possible Cause: This error usually comes when some firewall between client and server is blocking the ports used by VPN tunnel.
a> PPTP port (TCP port 1723) is blocked by a firewall/router. [Applicable to tunnel type = PPTP]
b> L2TP or IKEv2 port (UDP port 500, UDP port 4500) is blocked by a firewall/router.
Possible Solution: Enable the port (as mentioned above) on firewall/router. If that is not possible, deploy SSTP based VPN tunnel on both VPN server and VPN client – that allows VPN connection across firewalls, web proxies and NAT.