从表单发送邮件将无法正常工作

Question

我知道这是一个已经回答很多的问题，我已经阅读了其中的一些问题，但我似乎无法让我的发送邮件功能正常工作。所以基础知识是我有一个HTML联系表格：

<form id="contact" action="mail_handler.php" method="post">
                    <div class="col-md-6">
                      <fieldset>
                        <input name="name" type="text" class="form-control" id="name" placeholder="Your name..." required="">
                      </fieldset>
                    </div>
                    <div class="col-md-6">
                      <fieldset>
                        <input name="email" type="email" class="form-control" id="email" placeholder="Your email..." required="">
                      </fieldset>
                    </div>
                    <div class="col-md-12">
                      <fieldset>
                        <textarea name="message" rows="6" class="form-control" id="message" placeholder="Your message..." required></textarea>
                      </fieldset>
                    </div>
                    <div class="col-md-12">
                      <fieldset>
                        <button type="submit" value="Submit" class="btn">Send Message</button>
                      </fieldset>
                    </div>
                  </form>

这附加了一个名为mail_handler.php的外部文件，这似乎是我无法让我的文件工作的地方。

<?php

    $email = $_POST["email"]; //users email
    $name = $_POST["name"]; //users name
    $msg = $_POST["message"]; //users message
    $to = "email@mydomain.co.uk"; //my email
    $subject = "New online enquiry"; //subject line
    $headers = "From: $email \n"; //who is the email from 
    $message = "Name: $name \n sent the following enquiry: $msg"; //email content
    $user = "$email";
    $usersubject = "Thank You"; //subject for user email
    $userheaders = "From: enquiries@samsonvilliers.co.uk \n"; //who email is from
    $usermessage = "Thank you for sending a message, we will be in touch soon.";//thank you message to users email
    mail($to,$subject,$message,$headers); //mail to me
    mail($user,$usersubject,$usermessage,$userheaders); //mail to user
    header('Location: send_mail.html'); //send to a new page with thank you message.

?>

我尝试用很多不同的方式改变代码，但似乎没有任何工作，我确信我犯了一个非常简单的错误，但任何指导都会非常感激。