Windows 10: Can't connect with Vpn L2TP

Can anyone help me? I have a vpn problem with this error message capture below. I found a post saying it's because of windows update KB5009543. But I don't have this update in my system. Even after uninstalling the other recent update, still the same error.I still have access to this L2TP vpn before last night 04/19/2022.

:)

 

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***

 

Unable to connect Windows Phone 10 L2TP VPN through a NAT-T environment configuration

I'm running a L2TP/IPsec VPN behind a NAT-T router/firewall, and have configured appropriate ports for port forwarding to the VPN server.

I've discovered that the Windows Platform requires a registry entry in order to work in this environment.

Configure L2TP/IPsec server behind NAT-T device - Windows Server

Unfortunately, I'm currently unable to connect the Windows Phone10 (Nokia Lumia 950) to the VPN, and I'm assuming this is because Windows Phone 10 does not support L2TP/IPsec VPN behind a NAT-T router/firewall.

Is there a way to support this connectivity for a Windows Phone? Is there a planned update to support this type of configuration?

 

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.