How do i properly install flask-socketIO?

问题

I have installed multiple times Flask-socketio on my mac, closely reading the instructions and installing the requirements (eventlet/gevent). Athough when i run my simple code to test, it either says that i have not imported the modules or show nothing until i open index.html in my browser where it then displays : The client is using an unsupported version of the Socket.IO or Engine.IO protocols (further occurrences of this error will be logged with level INFO)

Here is my app.py code:

from flask import Flask
from flask_socketio import SocketIO, send

app = Flask(__name__)
app.config['SECRET_KEY'] = 'hello'
    
socketio = SocketIO(app, cors_allowed_origins='*')
@socketio.on('message')
def handle(msg):
    print("message: "+msg)
    send(msg, bradcast=True)

if __name__ == '__main__':
    socketio.run(app)

And here is my terminal window:

Here is my index.html code (if needed):

<html>
<head>
<title>Chat Room</title>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/1.4.8/socket.io.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script>
</head>
<body>
<script type="text/javascript">
$(document).ready(function() {

    var socket = io.connect('http://127.0.0.1:5000');

    socket.on('connect', function() {
        socket.send('User has connected!');
    });

    socket.on('message', function(msg) {
        $("#messages").append('<li>'+msg+'</li>');
        console.log('Received message');
    });

    $('#sendbutton').on('click', function() {
        socket.send($('#myMessage').val());
        $('#myMessage').val('');
    });

});
</script>
<ul id="messages"></ul>
<input type="text" id="myMessage">
<button id="sendbutton">Send</button>
</body>
</html>

Thank you for your help