Post data with XMLHttpRequest not working

The code below fails to load a response.
If I Run the Test I pass it, but when I click on the button, the innerHTML doesn’t get updated, and that because I guess the server didn’t give me back any response.
I’m using chrome, in the dev tools “network” tab, checking for XHR I see posts request initially pending, then failing after ~45 seconds.
Following are the Request Payload

  1. {userName: “Giacomo”, suffix: " loves cats!"}
  2. userName: “Giacomo”
  3. suffix: " loves cats!"

Your code so far

document.addEventListener('DOMContentLoaded', function(){
  document.getElementById('sendMessage').onclick = function(){

    const userName = document.getElementById('name').value;
    const url = '';
    // Add your code below this line
    const xhr = new XMLHttpRequest();'POST',url,true);
    xhr.setRequestHeader('Content-Type','application/json; charset=UTF-8');
    xhr.onreadystatechange = ()=>{
      if (xhr.readyState == 4 && xhr.status ==201){
        const serverResponse = JSON.parse(xhr.response);
        document.getElementsByClassName('message')[0].textContent = serverResponse.userName + serverRespone.suffix;
    const body = JSON.stringify({userName: userName, suffix: 'love cats!'})

    // Add your code above this line

body {
  text-align: center;
  font-family: "Helvetica", sans-serif;
h1 {
  font-size: 2em;
  font-weight: bold;
.box {
  border-radius: 5px;
  background-color: #eee;
  padding: 20px 5px;
button {
  color: white;
  background-color: #4791d0;
  border-radius: 5px;
  border: 1px solid #4791d0;
  padding: 5px 10px 8px 10px;
button:hover {
  background-color: #0F5897;
  border: 1px solid #0F5897;

<h1>Cat Friends</h1>
<p class="message box">
Reply from Server will be here
<label for="name">Your name:
  <input type="text" id="name"/>
<button id="sendMessage">
  Send Message

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.100 Safari/537.36.

Challenge: Post Data with the JavaScript XMLHttpRequest Method

Link to the challenge:

Probably Typo in ‘serverRespone.suffix’