ASA Dedicated Server Using VPN

[Xyx3r]

Hi everyone.
So I have a problem running ASA Dedicated server behind VPN.

My dedicated server is just my other computer.
My internet connection don't have public IP (behind NAT from ISP), in other word i have no control over network coming to the public facing IP that is own and controlled by my ISP.

So, to tackle the issue, i rent a cheap VPS with public IP address and Setup a VPN Server with it.

let say the IP of said server is 199.99.123.12
and the VPN Server IP is 10.9.0.1
and i installed the VPN Client on my Dedicated Server with the VPN IP of let say 10.9.0.2
and the public IP of my ISP let say 133.33.321.21

In order to connect to the Game Server, i would enter the public IP of the VPN Server
199.99.123.12:7777 or 199.99.123.12:27015

I have no problem with the port forwarding from my VPN Server to the Game server.
I run Ark Survival Evolved with this exact configuration.

With ASE, the server can be accessed both from LAN and from 199.99.123.12:27015
but with ASA, my dedicated server not shown either from Steam Server Browser (LAN or INTERNET), even from the Favorites it is not accessible, it always says "Failure, unable to connect to server, app id specified by server is invalid".
Even when I try to access the server from the same machine running the game server, same result.

But, using battleMetrics Site I could discover my server, only it is displaying the public IP address from my ISP rather than my VPN Server IP. aka 133.33.321.21:7777, and of course I cannot connect using that IP address because the port is not forwarded.

Does anybody have any idea what causing this?
and how does battlemetrics discover my Server while ARK Game itself can't?