Can't connect to VPN

If you are trying to connect to a corporate VPN and receive the following error: -

The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer

There is a high likelihood that you need to make a change in the registry and then restart your machine. To do this, follow these steps: -

1. Click Start and type regedit and press OK
   
2. Navigate to the following registry key - HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent
   
3. Look in the right panel for the following RegValue - AssumeUDPEncapsulationContextOnSendRule (if it doesn't exist, create it as a type DWORD)
   
4. Make sure the Data Value is set to 2
   
5. Exit regedit
   
6. Restart the machine
   

The above changes should allow a VPN connection to connect to the VPN correctly.

Here is the Microsoft Knwoledgebase article to support the above: -

https://support.microsoft.com/en-us/help/926179/how-to-configure-an-l2tp-ipsec-server-behind-a-nat-t-device-in-windows

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