Windows 10: Error: 788, when connecting to L2TP VPN

Hi there, recently I got this error when connecting to "L2TP/IPSec with certificate" VPN. I'm not sure what cause this.

I have already follow some of this steps with no luck :

• Adding AssumeUDPEncapsulationContextOnSendRule
• Restarting both IKE and IPSec services
• Allowing both CHAP and MS-CHAP v2
• Reset network connection
• Connect to different provider
• Re-adding VPN settings

There also little bit information can be found in the event viewer :


CoId={AEE0E2A8-34DF-41BB-B5F0-0458EFD41751}: The user xxx\xxx has started dialing a VPN connection using a per-user connection profile named yes. The connection settings are:
Dial-in User = *\
VpnStrategy = L2TP
DataEncryption = Requested
PrerequisiteEntry =
AutoLogon = No
UseRasCredentials = Yes
Authentication Type = PAP
Ipv4DefaultGateway = Yes
Ipv4AddressAssignment = By Server
Ipv4DNSServerAssignment = By Server
Ipv6DefaultGateway = Yes
Ipv6AddressAssignment = By Server
Ipv6DNSServerAssignment = By Server
IpDnsFlags =
IpNBTEnabled = Yes
UseFlags = Private Connection
ConnectOnWinlogon = No
IPsec authentication for L2TP = Machine certificate.


CoId={AEE0E2A8-34DF-41BB-B5F0-0458EFD41751}: The user xxx\xxx is trying to establish a link to the Remote Access Server for the connection named yes using the following device:
Server address/Phone Number = xxx.xxx.xxx.xxx
Device = WAN Miniport (L2TP)
Port = VPN3-1
MediaType = VPN.


CoId={AEE0E2A8-34DF-41BB-B5F0-0458EFD41751}: The user xxx\xxx dialed a connection named yes which has failed. The error code returned on failure is 788.


***Original title: VPN Error 788***

:)

 

L2TP VPN on Lumia 950 giving error code 812

Hello,

I recently purchased a Lumia 950 (AT&T running Windows 10 Mobile build 10.0.10586.0.

When I configure my work IPSec L2TP VPN connection on my phone and then attempt to connect, it attempts to connect, then fails displaying the error:

The VPN connection failed with error code 812.

This seems to happen after the credentials are accepted.

During the connection attempt on the phone, the status display progresses as follows:

• Connecting to <address of my VPN server>
• Verifying your credentials
• Connecting to <address of my VPN server>
• The VPN connection failed with error code 812.

When I look at the logs of my VPN server, a connection is actually established successfully by the client, then immediately terminated.

I'm not positive who is terminating the connection on who (client or server).

VPN Settings configured on the Lumia 950 are as follows:

Connection name: My Work

Server name or address: <address of my VPN server>

VPN Type: L2TP/IPsec with pre-shared key

Pre-shared key: <pre-shared key that is configured on my VPN server & working on other devices>

Type of sign-in info: User name and password

I have typed the username & password in again multiple times to confirm it is correct. It is.

Furthermore, I have a Lumia 925 running Windows Phone 8.1. It connects perfectly using these same settings.

It seems something changed in Windows 10 Mobile that caused this VPN connection to stop working.

Do you have any suggestions on how I might be able to get this resolved?

I really need the VPN to be working.

Thanks!

-

Doug Mortensen

Impala Networks

 

Vpn ( trusted Vpn)

I use Nordvpn. You can connect 6 devices. You can choose servers by country or by a list of each server in each country, use UDP or HTTP, PPtP, L2TP. Double VPN, TOR via VPN. There`s are apps for android and iphones as well as DNS leak protection.

 

Windows 10 L2TP VPN connection issue

I have a Windows 10 client which has been configured to connect to an L2TP VPN.

To get the connection to work, I had to add the "AssumeUDPEncapsulationContextOnSendRule" registry Key, and then totally disable Windows Firewall—the VPN connects perfectly this way.

However, I cannot get the VPN to connect with the Windows Firewall enabled and I really need to keep the Windows Firewall enabled and be able to connect to the L2TP VPN.

I have also allowed...

• Protocol 50 (ESP) in and out
  
• UDP 1701, 4500, 500 in and out
  

However the VPN still only connects if I totally disable the Windows Firewall and not with it enabled.

Question: Any help or guidance suggested to further troubleshoot this problem?