FIX: Cannot connect to L2TP VPN on Windows 10

Elena Constantinescu
by Elena Constantinescu
VPN Expert & Privacy Advocate
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  • If you cannot connect to L2TP VPN on Windows 10, there might be a problem with your VPN client or OS setup. However, if it's a VPN server-side issue, you must fix it there or contact the server admin.
  • Our complete guide shows how to fix L2TP VPN connection issues on Windows 10 one step at a time. We prepared 12 solutions and 1 better alternative for your PC to prevent recurring problems.
  • To find out more, check out the most common VPN errors and their solutions.
  • Visit our VPN Troubleshooting Hub to see what else you can do with a VPN.
fix cannot connect to L2TP VPN on Windows 10
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If you created an L2TP VPN connection on Windows 10 but cannot connect, you can fix this problem by trying the workarounds in this guide.

A failed L2TP VPN connection could occur due to several reasons, such as:

  • Invalid username and password
  • Inaccurate server name or address
  • Wrong certificate or pre-shared key
  • Bad proxy settings
  • Faulty encryption settings on the server side
  • Incorrect authentication settings
  • The connection is blocked by your firewall
  • The VPN server, client, or both are behind NAT

Our complete step-by-step guide below shows how to fix L2TP VPN connection issues on Windows 10. If possible, you should also check the L2TP connection settings on the VPN server.

How do I fix L2TP VPN connection issues on Windows 10?

1

Check the username and password

check the L2TP VPN username and password on Windows 10

  • Right-click the Start button and go to Network Connections.
  • Click VPN on the left side.
  • Select your L2TP VPN connection and click Advanced options.
  • Press Edit.
  • Retype your User name and Password.
  • Click Save.

If your entered your VPN credentials wrong or if they were changed by the VPN server administrator in the meantime, then a simple update to your username and password should help if you cannot connect to L2TP VPN on Windows 10.


Are you getting a VPN authentication failed error message? Find out how to quickly fix it.


2

Check the server name or address

check the L2TP VPN server name or address on Windows 10

  • Go to VPN settings and choose the L2TP VPN profile.
  • Click Advanced options and then Edit.
  • Retype your Server name or address or try a different one.
  • Click Save.

The L2TP VPN connection problem could be caused by a simple typo made to your server name or address, so make sure to re-enter this information. Otherwise, the remote L2TP VPN server might not be working. In that case, you can try connecting to another server if possible.

3

Check the certificate or pre-shared key

check the L2TP VPN pre-shared key on Windows 10

  • Go to VPN settings and select your L2TP VPN connection.
  • Click Advanced options and then Edit.
  • Retype your Pre-shared key.
  • Click Save.

Similar to the username and password situation, the pre-shared key you initially typed could have been wrong or changed by the VPN server administrator. After adding the new pre-shared key, try to connect to the L2TP VPN again to see if it works now.

However, if there’s an issue with the L2TP VPN certificate, there’s nothing you can do on the VPN client side. You have to either verify the certificate on the server or contact the administrator for help.

Alternatively, try switching between L2TP/IPsec with certificate and pre-shared key, in case the server admin changed the VPN type.

4

Check the VPN proxy settings

check VPN proxy settings on Windows 10

  • Go to VPN settings and click your L2TP VPN profile.
  • Select Advanced options.
  • Scroll down to VPN proxy settings
    • If you need to redirect your VPN connection to a proxy server, make sure the proxy settings are correct.
    • Otherwise, remove the proxy by selecting None.
  • Click Apply.

Even if you need to use a VPN proxy server, disable it temporarily and try to connect to L2TP VPN again to see if it’s really the proxy’s fault. It might not be working properly.

In that case, you should fix proxy server connection issues, use another proxy, or keep it disabled.

5

Check the encryption settings

set VPN optional data encryption on Windows 10

  • Right-click the Start button and go to Network Connections.
  • Click Change adapter options.
  • Right-click your VPN connection and select Properties.
  • Switch to the Security tab.
  • Set Data encryption to Optional encryption (connect even if no encryption).
  • Click OK.

If the VPN server has encryption issues, this could be the reason why you cannot connect to L2TP VPN on Windows 10. By making the encryption optional, you might be able to temporarily solve this problem.

However, encryption is a critical component of a VPN connection, so you should contact the VPN server administrator to fix this issue as soon as possible.

6

Check the authentication settings

set VPN security protocols on Windows 10

  • Go to Network Connections > Change adapter options.
  • Right-click your VPN and go to Properties.
  • Switch to the Security tab.
  • At Authentication, select Allow these protocols.
  • Enable Challenge Handshake Authentication Protocol (CHAP).
  • Enable Microsoft CHAP Version 2 (MS-CHAP v2).
  • Click OK.

L2TP connection issues are typically caused by invalid VPN authentication settings. Try the configuration above to see if it works. Otherwise, you should get in touch with the VPN server administrator and request assistance.

7

Open L2TP ports in your firewall

open ports for L2TP on the Windows firewall

  • Click the Start button, type firewall, and select Firewall & network connection.
  • Click Advanced settings and Yes if prompted by UAC (User Account Control).
  • Select Inbound Rules on the left side.
  • Click New Rule on the right actions panel.
  • At Rule Type, select Port.
  • At Protocol and Ports, select UDP with Specific local ports and type 1701, 500, 4500.
  • Set Action to Allow the connection if it is secure.
  • Enter any rule name and click Finish.
  • Go to Outbound Rules and do the same.

If your L2TP VPN connection gets blocked by the firewall, then you have to open the correct ports for sending and receiving network traffic. However, the firewall configuration above should also be made on the VPN server.

8

Make an easy tweak to the registry

add AssumeUDPEncapsulationContextOnSendRule to regedit

  • Press Ctrl+R, type regedit, hold down Shift, and press Enter.
  • Click Yes if prompted by User Account Control.
  • Delete what’s inside the address bar on top.
  • Paste the following address and press Enter:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent
  • Open Edit menu > New and click DWORD (32-bit) Value.
  • Set AssumeUDPEncapsulationContextOnSendRule as the value name.
  • Right-click AssumeUDPEncapsulationContextOnSendRule and press Modify.
  • Set Value data to 2.
  • Set Base to Hexadecimal.
  • Click OK.
  • Next, paste this address and hit Enter:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan
  • Open Edit menu > New and click DWORD (32-bit) Value.
  • Set ProhibitIpSec as the value name.
  • Right-click ProhibitIpSec and click Modify.
  • Set Value data to 0.
  • Set Base to Hexadecimal.
  • Click OK.
  • Restart your computer.

If the VPN server, client, or both as behind a NAT, such as a home router, you can use the registry tweaks above to fix the NAT traversal problem.

A faster way to tweak the registry and make Windows 10 connect to L2TP VPN by entering a couple of lines of code in Command Prompt (look inside the article to see how).

9

Reinstall the network adapters

uninstall L2TP network adapters from Device Manager

  • Right-click the Start button and go to Device Manager.
  • Expand the Network adapters menu.
  • Right-click TAP-Windows Adapter V9 and select Uninstall device.
  • Leave Delete the driver software for this device unchecked.
  • Click Uninstall.
  • Do the same for WAN Miniport (L2TP) and WAN Miniport (Network Monitor).
  • Open the Action menu and select Scan for hardware changes.

If you uninstall the network adapters but without also removing the driver software, Windows will automatically reinstall them. Fixing Windows 10 network adapter problems is a practical way to handle the L2TP VPN connection issue.

10

Update the network drivers

update L2TP network adapters from Device Manager

  • Go to Device Manager and expand the Network adapters menu.
  • Right-click TAP-Windows Adapter V9 and select Update Driver.
  • Choose Search automatically for updated driver software.
  • Follow the on-screen instructions.
  • Do the same for WAN Miniport (L2TP) and WAN Miniport (Network Monitor).

If you receive The best drivers for your device are already installed message, you can look for newer driver versions in Windows Update, install the drivers manually, or find and install newer device drivers automatically using driver update tools.

11

Restart the IPsec service

restart IPsec services in Windows

  • Click the Start button, type Services, and press Enter.
  • Find and right-click IKE and AuthIP IPsec Keying Modules.
  • Press Restart (or Start if the service is stopped).
  • Do the same for IPsec Policy Agent.

Windows 10 uses L2TP in combination with IPsec to establish a secure tunnel. If there’s a problem with IPsec, not with the L2TP, then you can restart its service.

It’s also a good way to fix VPN error 789.

12

Turn off Xbox Live Networking Service

 disable Xbox Live Networking Service on Windows

  • Go to Services and locate Xbox Live Networking Service (last on the list).
  • Double-click this entry and set Startup type to Disabled.
  • Click Apply.
  • Restart your PC.

Xbox Live Networking Service uses the IPsec protocol for chatting and multiplayer features. However, the Windows 10 L2TP VPN also uses IPsec. And many ISPs don’t permit two or more simultaneous IPsec connections.

Therefore, you can disable Xbox Live Networking Service to fix this problem, especially if you don’t play Xbox multiplayer games. This is also a workaround to fix VPN error 809.

13

Use a premium VPN service

Private Internet Access

If you don’t want to deal with recurring L2TP connection issues on Windows 10, we suggest upgrading to a premium VPN service like Private Internet Access (PIA).

Owned by Kape Technologies, this tool can be installed on a wide range of devices, including Windows, macOS, Linux, Android, and iOS.

PIA uses OpenVPN and WireGuard to secure your network traffic, but you can also opt for L2TP manual configuration mode using PIA’s L2TP login credentials. The app supports native port forwarding, a kill switch, static and dynamic IP addresses, together with an ad and malware blocker.

You can use PIA to unblock Netflix US and other streaming services, enable split-tunneling mode, protect your DNS queries using exclusive DNS servers, and even change the NAT type with a VPN. Plus, if you run into any problems, you can take advantage of its 24/7 live chat support.

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In conclusion, the 12 solutions above should help you if you cannot connect to L2TP VPN on Windows 10. However, if you don’t want to worry about such problems anymore, we suggest skipping to the 13th step and using PIA instead. It’s also the best VPN for Google Chrome.

FAQ: Learn more about L2TP VPN connection issues

  • How do I fix L2TP connection attempt failed?

To fix L2TP connection attempt failed, also known as VPN error 789, reset the network adapter, check the certificate, or restart the IPsec service.

  • How do I connect to L2TP VPN?

Add a VPN connection using the Windows 10 built-in VPN provider and set VPN type to L2TP/IPsec with certificate or L2TP/IPsec with pre-shared key.

  • How do you fix The connection was terminated by the remote computer before it could be completed?

To fix The connection was terminated by the remote computer before it could be completed, also known as VPN error 628, check your login credentials, temporarily turn off your firewall and antivirus tool, or try a different VPN protocol.