Can't send a request to a server through a VPN connection

My question:
Can’t send a request to a server through a VPN connection.

Details (like screenshots):
I have a Node.js with express.js server which runs on a server and I connect to that server through a VPN, when I try to send a request VIA Postman, it fails and the request is not sent.

How I found the problem:

I’ve already tried:
I tried to ping the IP of the server while I’m connecting to the server VIA VPN and the ping worked, also I have tried to set up the proxy in postman but this didn’t work.