How to Fix 'The L2TP Connection Attempt Failed' Processing Error

Windows Networking
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Originally published at: How to Fix 'The L2TP Connection Attempt Failed' Processing Error

An L2TP connection uses the Layer 2 Tunneling Protocol and is used mostly for supporting Virtual Private Networks. A Virtual Private Network(VPN) is used to mask the origin of connection by reflecting the connection over a server located in a different area than the origin of the connection. This can help many people to hide…

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Is this happening after the 22H2 update?

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Try the suggestion above in my comment let me know how it goes.

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Okay then try this:-

  1. Search for CMD and run it as an administrator.
  2. Now type the following commands and restart your computer.

sc config IKEEXT start= demand
sc config PolicyAgent start= demand

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It’s possible that your Windows Firewall is blocking the connection try disabling it for testing and check if the issue still persists. Here is how you can disable it.

  1. Press and hold the “Windows + R” keys together to open the Settings app.
  2. Head over to “Update & Security > Windows Security > Firewall & Network Protection”
  3. Now make sure to set all these settings to off click all the settings one by one and set them to off.
  4. Please revert them back to on after checking as it can cause serious security issues.
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Do you have any 3rd Party VPN Installed on your Computer? If yes please try uninstalling them and check if the issue still persists.

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I just set the vpn type to automatic and everything goes well.

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Thank you, that worked for me. Really hate these buggy updates

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Correct even with 22h2 it is still giving me the issue

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Win 11 Tried everything above still not working

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This worked for me… Thank you sooo much.

Placide, from Burundi.

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THIS IS NOT THE PROBLEM.
What broke is a Microsoft Update! This is on ALL Windows 10+ PC’s I have all these settings already set.
KB5009543 is the issue! You can manually uninstall it CONTROL PANEL → PROGRAMS AND FEATURES → SHOW WINDOWS UPDATES → Uninstall the KB500943.
It sounds like it was a windows update foobar as they have already released fixes, but it is about 6 different KB’s depending on the 6 different releases of Windows 10 or 11. So the best (if you’re not completely paranoid about security) is to uninstall KB500943 and wait for the next band of full windows patches automatically install.

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I’ve made this registry change. I still can’t connect. In the event log I receive event ID 20117 from RasClient with error code 789.

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Hey Richard,

Can you try using this command? Follow the Steps Below:-

  1. Search for Command Prompt and run it as an administrator.
  2. Type the following command then press enter:-

reg add “HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesPolicyAgent” /v “AssumeUDPEncapsulationContextOnSendRule” /t REG_DWORD /d “2” /f

Restart your computer and check to see if the issue persists.

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Followed every step in this article to the letter. Still no VPN. Error “The network connection between your computer and the VPN server could not be established because the remote server is not responding. This could be because one of the network devices (e.g. firewalls, NAT, routers, etc) between your computer and the remote server is not configured to allow VPN connections. Please contact your Administrator or your service provider to determine which device may be causing the problem.”

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Hi im not work no 3rd party vpn installed
Please help

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Did not work on my Lenovo Windows 10. Please help!

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Did not solve my problem on Windows Server 2008 R2 VPN.