error when trying to connect to python socket using websocket javascript client

I am trying to make a connection from my javascript client in a browser to my python server and to send data from the server to the client, but when trying to connect I get the error: failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED

I tried using wss instead of ws. I also tried using socket.io instead of websocket, which wasn't helping either. I don't remember all the things I tried but none of them helped.

Javascript client:

var conn = new WebSocket('ws://localhost:2001');
    conn.onmessage = function (event) {
     console.log(event.data);

Python server:

# Echo server program
import socket

HOST = 'localhost'
PORT = 2001 
def sendSensorData(data):

    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind(HOST, PORT)
        s.listen(1)
        conn, addr = s.accept()
        with conn:
            print('Connected by', addr)
            while True:
                print(data)
                message = str(data).encode()
                try:
                # if not data: break
                    conn.sendall(message)
                except BaseException as e:
                    print (e)

Edit: This is the error from python:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/threading.py", line 917, in _bootstrap_inner
    self.run()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "/Users/joep/Documents/GitHub/Walnut-installation-web-app/testAPI/workers/sensorStream.py", line 26, in sensorStream
    sendSensorData.sendSensorData(data)
  File "/Users/joep/Documents/GitHub/Walnut-installation-web-app/testAPI/functions/sendSensorData.py", line 19, in sendSensorData
    conn.send(message)
BrokenPipeError: [Errno 32] Broken pipe

Hopefully it is a simple trick to fix it.