IpSec Client VPN not working on multiple Windows Machines

[AutoDealer]

I have several Windows Pc's that cannot establish a client VPN. The error in the event viewer is 789.  

[alemabrahao]

Error 789 can occur due to a mismatch in the PSK. Ensure that the PSK is correct and does not end with a special character.

Unable to Connect to Client VPN from Some Devices - Cisco Meraki

This tool can help you.

https://www.ifm.net.nz/cookbooks/meraki-client-vpn.html

[AutoDealer]

I have done these steps, Cisco support claims they are able to use my VPN from their machines.  Therefore it is an issue with "Client Setup". I'm assuming there is something wonky in the windows built-in VPN service on these machines.

[alemabrahao]

Update windows or uninstall the latest update. I suggest you to use Anyconnect instead of L2TP connection.