It seems that you are experiencing issues with the L2TP VPN connection after security updates KB5009543 and KB5009566 on Windows 11. If you have already removed the updates and the issue persists, there are a few additional steps you can take to troubleshoot and potentially resolve the problem: 1.
Check VPN Configuration: Verify that the VPN settings in Windows 11 are correctly configured for the L2TP VPN connection. Ensure that the server address, your credentials, and other settings are accurate. 2.
Network Adapter: Check the network adapter settings on your system. Ensure that the correct network adapter is being used for the VPN connection and that it is working correctly. 3.
Firewall and Antivirus Software: Temporarily disable any third-party firewall or antivirus software to check if they are causing any interference with the VPN connection. 4.
L2TP Ports: Ensure that ports such as UDP 500 and UDP 4500 are open on your network and any firewall settings. L2TP VPN connections require these ports to be open for communication. 5.
System File Checker: Run the System File Checker tool to scan and repair potentially corrupted system files that may be causing the VPN connection issue. Open Command Prompt as an administrator and run:
6.
Network Reset: Try resetting the network settings in Windows 11 to default. This will remove and reinstall all network adapters and set settings back to their original state. 7.
Update Network Drivers: Ensure that your network adapter drivers are up to date. You can update them manually through the Device Manager or by visiting the manufacturer's website for the latest drivers. 8.
Additional Steps: Try connecting to the L2TP VPN from a different network (if possible) to rule out any local network issues causing the problem. If these steps do not resolve the L2TP VPN connection issue, you might consider reaching out to your VPN service provider for additional assistance or looking for specific troubleshooting steps related to L2TP VPN connectivity on Windows 11.
