javascript – WebRTC webapp problem: Websocket connection issue

I am a beginner to WebRTC. I used this simple source code to build a video chat webapp:

github.com/itsallbinary/video-conf-tutorial/tree/master/src/main/webapp

I use Hostinger VPS, with a dedicated IP and root access, and I confirmed with their customer support team that this supports Socket connections. I have SSL, certificate issued from “R3”, which is issued by “ISRG Root”.

However, while i run the webapp, this happens: (Chrome Console)

Connected to signaling endpoint. Now initializing.

 Requesting local stream

  Received local stream

Using video device: Integrated Camera (13d3:5415)

 Using audio device: Default - Microphone Array (Realtek(R) Audio)

 Start complete

WebSocket connection to 'wss://site.com/video-conf-tutorial/signal' failed: 
(anonymous) @ conf.js?reloads=true:19


 Starting addLocalStreamToPeerConnection

 localStream tracks added