Contact form issue?

Question

I have contact form on my website(hosted with Hostinger) it contains 3 fields , i am trying to receive the message on my email so i have created the HTML tags and .php handler.

The problem is nothing happened when i click submit , here is my HTML and PHP:

HTML:
<form method="POST" action="contact-form-handler.php">
    <label class="nameLabel">Name:        
    <input type="text" name="name" id="name" required>
    </label>
    <label class="emailLabel">Email:
    <input type="email" name="email" id="email" required>
    </label>
    <label class="messageLabel">Message:
    <textarea class="textarea" name="message" id="message" required>                            
    </textarea>
    </label>
    <input  type="submit" class="button"   value="SEND">
</form>

Here is my .php

<?php
    $name = $_POST['name'];
    $visitor_email = $_POST['email'];
    $message = $_POST['message'];


    $email_from ='email@gmail.com';

    $email_subject ="Form Submission";

    $email_body = "User Name: $name.\n".
                    "User Email: $visitor_email.\n".
                        "User Message: $message.\n";


    $to = "2ndemail@yahoo.com";

    $headers = "From: $email_from \r\n";

    $headers .= "Reply-To: $visitor_email \r\n";

    mail($to,$email_subject,$email_body,$headers);
    header("Location: index.html");
?>