Has anyone had this error before?
"The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer"
Alguien ha tenido este error?
"Error en el intento de conexión L2TP porque el nivel de seguridad encontró un error de proceso durante las negociaciones iniciales con el equipo remoto"
I've seen similar but not that exact description. Are you getting a particular windows error code in the event viewer or the pop-up window? You could be hitting the 789 error. There are a few examples outlined here https://documentation.meraki.com/MX/Client_VPN/Troubleshooting_Client_VPN and most of the error codes are listed here https://support.microsoft.com/en-us/help/824864/list-of-error-codes-for-dial-up-connections-or-vpn-c...
I'm with @MerakiDave on it being the 789 error.
I have also had this error by using a PSK that was too complex. I don't know which, some some special characters just don't work on all clients.
If in doubt, make your PSK simple, like "password". If that works then you know it is this issue and you can start making it more complex.
Quick note to let you know that Windows 10 seem to have the horrible tendency of removing the security option every time you disconnect from VPN, reboot your PC, do updates, click the mouse on the Desktop or look away from the screen.
Make sure you have "Require encryption" selected and under "Allow these protocols:" tick "Unencrypted password (PAP)"
This should theoretically help as well.
Just want to share this method its applicable on W10 user's i just recently apply this to one of our client.
On your VPN network settings check allow these protocols and check Unencrypted Password (PAP)
On the Windows 10 machine, open the registry and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent, make a new DWORD 32 bit value, call it AssumeUDPEncapsulationContextOnSendRule, give it a value of 2, then reboot the Windows 10 machine. It should connect just fine.
This one works for me