Wondering how to resolve VPN L2TP connection attempt failed on Windows 10 & 11? We can help you.

As part of our Server Management Services, we assist our customers with several VPN queries.

Today, let us see how our Support techs assist with this process.

How to resolve VPN L2TP connection attempt failed on Windows 10 & 11?

Usually, issue occurs if it is link to the incorrect configuration operating system like Windows 10 in this case.

This generic error is thrown when the IPSec negotiation fails for the L2TP/IPSec connections.

Also, some of the other causes are listed below:

• L2TP based VPN client (or VPN server) is behind NAT
• Secondly, wrong certificate or pre-shared key is set on the VPN server or client
• A machine certificate or trusted root machine certificate is not present on the VPN server
• Machine Certificate on VPN Server does not have Server Authentication as the EKU

Today, let us see the steps followed by our Support Techs to resolve it.

1. Reset network adapter

• Firstly, press Windows key + X and select Device Manager.
• Then, identify your network adapter and right-click on it then select Uninstall device.
• Next, click on Uninstall to confirm.
• Finally, restart your computer. The device will reinstall and should reset it to default settings.

Refreshing the network adapter driver can make this problem go away quickly so make sure you try it out by performing the steps above.

2. Check the certificate

It is very important to ensure the correct certificate is used both on the client and the server-side.

In case the two don’t match, you won’t be able to use the virtual private network.

You might need to renew the certificate with your provider.

If you are using a Pre Shared Key (PSK), ensure that the same PSK is configured on the client-side, and the VPN server machine.

3. Use a reliable VPN service

It is very likely that the root of this problem is that the servers you use are not very optimal for your connection.

For this reason, it is recommend to use a top-level VPN service.

To make sure you will not encounter this kind of issue in the future, look for a VPN service that has a large number of servers across the globe.

That guarantees an increase chance of server availability and functionality.

We recommend NordVPN because it has over 5 thousand servers across the globe, plus 1 thousand servers in the US alone.

Plus, it is easy to use, you don’t need any level of proficiency to get an optimal connection.

To get started, select the subscription plan of your choice, create an account and install it.

When the app is ready to open, connect to a secure server with just one click.

4. Re-enable IPSec on your computer

• Firstly, press the Windows key + R keyboard shortcut to start Run.
• Then, type services.msc and press Enter or click OK.
• Next, double-click the IKE and AuthIP IPSec Keying Modules service.
• Then, set the Startup type to Automatic. If the service is running, click Stop and then Start. If it’s disabled, just click Start.
• Find IPSec Policy Agent and double-click it.
• Set the Startup type to Automatic. If the service is running, stop it and start it again. If it’s not running, start it.
• Then, save the changes.
• Finally, restart your VPN service.

Once you have done all the steps above carefully, the VPN should work smoothly as the protocol settings have been reset to default.

[Stuck in between? We’d be glad to assist you]

Conclusion

In short, today we saw steps followed by our Support Techs resolve VPN L2TP connection attempt failure.