networking – Cannot connect to VPN Server using the SoftEther VPN client over internet

I set up a SoftEther VPN Server on a Windows machine. I can connect to it using the SoftEther VPN Client only in my private network but can’t connect to it from a public internet network I’m getting an Error Code 1 – unable to connect to the server.

I have disable the Windows Firewall but still not working. Any thing else I could try to get the connection happening?