VPN L2TP and Windows Client

Hello at all,
I have a problem with a L2TP VPN configured on Nebula.
I have a Firewall NSG100 and i have already configured a VPN L2TP and connection client side with the Windows native VPN. All of this worked since yesterday well.

Yesterday i have done a little modify, i have power on the IPSec VPN Server and configure that. After i have poweroff and save the configuration, and now, my L2TP over IPSec VPN server doesn't work already. With nebula the configuration is very simply, i can't change a lot of settings.

Thinks that i have already checked:
- I have the nebula cloud authentication login method i have tried to change the password and set again on Windows VPN but nothing;
- The public IP address of firewall is ok;
- i have checked the secret key and re-write that both server side and client side (no special character)
- i have already deactivate the Windows Update that seems blocking L2TP VPN Connection
- I have a Nebula Cloud Base Pack ( maybe is this the problem?)

This is an image server side (i have checked that the user of Nebula Cloud Authentication is already VPN authorized and since yesterday works fine):

Side Windows:



The Log on nebula