Cannot connect client to server using socket - php

Question

Motivation:
I want to update my front-end directly from the server.
I can't connect the client to the server. (Error on client)
Socket.io v4
Node.JS server runs on port 3000
Client on port 80
Server side
var express = require('express');
const { Server } = require("socket.io")
const http = require('http');
const Sockets = require('./sockets');
var app = express();
const miserver = http.createServer(app);
app.use(express.static(__dirname + '/public'));
const httpserver = miserver.listen(3000);
console.log("Servidor corriendo en el puerto 3000");
//incluir socket IO
const el_io = new Server(httpserver, {
cors: {
origin: "http://localhost:80",
methods: ['POST', 'GET'],
credentials: true
}
});
Sockets(el_io);
Client side
<script src="../socket.io.js"></script>
<script>
var socketIO = io('ws://localhost:3000/socket.io/?EIO=3&transport=websocket');
</script>

Answer 1

the socket run at port 80
Nothing in this code you show is running on port 80. You show the creation of ONE http server that is running on port 3000.
Also, this:
io('ws://localhost:3000/socket.io/?EIO=3&transport=websocket');
is wrong. The path and parameters are things that socket.io adds to the URL itself. You should just be doing this:
const socketIO = io('http://localhost:3000');
and, if you want to avoid CORs issues, you can tell socket.io to go directly to a webSocket like this:
const socketIO = io('http://localhost:3000', {transports: ['websocket']});