socket.io insufficient resources - react js and node - node.js

Question

I'm experimenting a bit with socket.io to create a chat app in real time.
Everything seems to work fine but after a few second socket.io gives me this error:
"websocket.js:50 WebSocket connection to 'ws://localhost:5000/socket.io/?EIO=4&transport=websocket&sid=gbx90aAo73oDoP86AAVP' failed: Insufficient resources"
What am I doing wrong?
Client
import React from "react";
import { useState, useEffect } from "react";
import { io } from "socket.io-client";
const App = () => {
const [conv, setConv] = useState([]);
const [input, setInput] = useState({
sender: "user",
text: "",
});
const socket = io("http://localhost:5000");
const handleChange = (e) => {
setInput({
sender: "user",
text: e.target.value,
});
};
const handleSubmit = (e) => {
e.preventDefault();
socket.emit("input", input);
};
useEffect(() => {
socket.on("output", (data) => {
setConv(data[0].messages);
});
}, [conv]);
return (
<div className="App">
<form onSubmit={handleSubmit}>
<h1>chat</h1>
<div id="messages">
{conv.map((msg, index) => (
<div key={index}>
<p>
{msg.sender}: {msg.text}
</p>
</div>
))}
</div>
<input onChange={handleChange} type="text" />
<input type="submit" />
</form>
</div>
);
};
export default App;
Server
const express = require("express");
const socketIo = require("socket.io");
const http = require("http");
const PORT = 5000;
const app = express();
const server = http.createServer(app);
const io = socketIo(server, {
cors: {
origin: "http://localhost:3000",
},
}); //in case server and client run on different urls
const MongoClient = require("mongodb").MongoClient;
MongoClient.connect("mongodb://localhost:27017", (err, db) => {
if (err) throw err;
console.log("connected");
const database = db.db("local");
const chat = database.collection("chat");
//connect to socket .io
io.on("connection", (socket) => {
// get chat from collection
chat.find().toArray((err, res) => {
if (err) throw err;
// emit the messages
socket.emit("output", res);
});
//handle input events
socket.on("input", (input) => {
let sender = input.sender;
let receiver = "bot";
let text = input.text;
// check if inside chat collection the members array contains the sender and receiver
chat.find({ members: { $all: [sender, receiver] } }).toArray((err, res) => {
if (err) throw err;
let senderInDb = res[0].members[0];
let receiverInDb = res[0].members[1];
//if yes then push the message to the messages array
if (sender === senderInDb && receiver === receiverInDb) {
chat.updateOne(
{ members: { $all: [sender, receiver] } },
{ $push: { messages: { sender: sender, text: text } } }
);
}
});
});
});
});
server.listen(PORT, (err) => {
if (err) console.log(err);
console.log("Server running on Port ", PORT);
});