An error occured while connection to VPN Server

[EdenGenesis]

Hello,

I'm contacting you because I have an issue when trying to connect to VPN.

Whenever I try, I get the following error message :
An error occured while connection to VPN Server
Error (Error code 2)
Protocol error occurred. Error was returned from the destination.


I never had such problem before, but on Windows 1O up to date, I get this ongoing issue.
I switched off Windows Defender, also allowed SoftEther VPN in the Windows Firewall, but nothing happen, I can't connect to VPN.

Any idea how I could make it works?

Hope to hear from you soon.

Best regards,
Eden

[EdenGenesis]

Update :

It only works when I use "UDP VPN" but doesn't work with the recommended "TCP VPN".

What are the difference btw? Why does it work when I use UDP?

Why TCP is recommended?

Thanks in advance.