Heroku with socket.io error 404

Hello guys

I deploy on app on heroku. I use socket.io to make a chat, it’s work fine on local but i’m can’t making this work online.

I try severals things. I post the last.

In my server side :

const app = express();
const cors = require('cors');
var chat = require('https').createServer(app)
var io = module.exports.io = require('socket.io').listen(chat)
const SocketManager = require('./SocketManager')
io.on('connection', SocketManager)

my client side :

const socketUrl = "https://teachonline.herokuapp.com"
export default class Layout extends React.Component {

	constructor(props) {
	  this.state = {

	componentWillMount() {

	*	Connect to and initializes the socket.
	initSocket = ()=>{
		const socket = io(socketUrl)
		socket.on('connect', ()=>{
			console.log("chat Connected");

I got two request when i do that : a get with a 200 as a response and juste after that a 404

You can see by yourselves : https://teachonline.herokuapp.com/chat

I can give you my Github if you want to check something else

If you have any idea of what am i doing wrong, i’m listening. I’m fighint with heroku for hours :’(