cURL Fails To Auto Post

[bits2017]

Hi,

I was searching for a tutorial that teaches how cURL can auto post and came across the following code. It is supposed to fill-in WP comment form. But for some reason I see no response on the commenting section on the blog:
https://www.atilus.com/top10internetmarketingblogs/

Why is that ?
If I run the script on my site then I see cURL fetches the page (the above link) but I see no response on the comment form.
If I run the script on my Xampp (localhost) then I see a complete white blank page. Why ?

<?php
$postfields = array();
$postfields["action"] = "submit";
$postfields["author"] = "programmer";
$postfields["email"] = "[e-mail]";
$postfields["url"] = "http://www.example.com/";
$postfields["comment"] = "Testing comment 1,2,3.";
$postfields["comment_post_ID"] = "123";
$postfields["_wp_unfiltered_html_comment"] = "0d870b294b";
//Url of the form submission
$url = "https://www.atilus.com/top10internetmarketingblogs/";
$useragent = "Mozilla/5.0";
$referer = $url; 
 
//Initialize CURL session
$ch = curl_init($url);
//CURL options
curl_setopt($ch, CURLOPT_POST, 1);
//We post $postfields data
curl_setopt($ch, CURLOPT_POSTFIELDS, $postfields);
//We define an useragent (Mozilla/5.0)
curl_setopt($ch, CURLOPT_USERAGENT, $useragent);
//We define a refferer ($url)
curl_setopt($ch, CURLOPT_REFERER, $referer);
//We get the result page in a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
//We exits CURL
$result = curl_exec($ch);
curl_close($ch);
 
//Finally, we display the result
echo $result;
?>