How do I send mail using a php contact form? – Jquery

So this contact form used to work, however now it loads and says mail sent when someone clicks submit but I never get any emails, what am I missing out?

<?php

// Replace this with your own email address
$siteOwnersEmail = '[email protected]';


if($_POST) {

   $name = trim(stripslashes($_POST['contactName']));
   $email = trim(stripslashes($_POST['contactEmail']));
   $subject = trim(stripslashes($_POST['contactSubject']));
   $contact_message = trim(stripslashes($_POST['contactMessage']));

   // Check Name
    if (strlen($name) < 2) {
        $error['name'] = "Please enter your name.";
    }
    // Check Email
    if (!preg_match('/^[a-z0-9&'.-_+]+@[a-z0-9-]+.([a-z0-9-]+.)*+[a-z]{2}/is', $email)) {
        $error['email'] = "Please enter a valid email address.";
    }
    // Check Message
    if (strlen($contact_message) < 15) {
        $error['message'] = "Please enter your message. It should have at least 15 characters.";
    }
   // Subject
    if ($subject == '') { $subject = "Contact Form Submission"; }


   // Set Message
   $message .= "Email from: " . $name . "<br />";
    $message .= "Email address: " . $email . "<br />";
   $message .= "Message: <br />";
   $message .= $contact_message;
   $message .= "<br /> ----- <br /> This email was sent from your site's contact form. <br />";

   // Set From: header
   $from =  $name . " <" . $email . ">";

   // Email Headers
    $headers = "From: " . $from . "rn";
    $headers .= "Reply-To: ". $email . "rn";
    $headers .= "MIME-Version: 1.0rn";
    $headers .= "Content-Type: text/html; charset=ISO-8859-1rn";


   if (!$error) {

      ini_set("sendmail_from", $siteOwnersEmail); // for windows server
      $mail = mail($siteOwnersEmail, $subject, $message, $headers);

        if ($mail) { echo "OK"; }
      else { echo "Something went wrong. Please try again."; }

    } # end if - no validation error

    else {

        $response = (isset($error['name'])) ? $error['name'] . "<br /> n" : null;
        $response .= (isset($error['email'])) ? $error['email'] . "<br /> n" : null;
        $response .= (isset($error['message'])) ? $error['message'] . "<br />" : null;

        echo $response;

    } # end if - there was a validation error

}

?>
 

And this is the contact form:

<form name="contactForm" id="contactForm" method="post" action="mail/mail.php">
                <fieldset>

                   <div class="form-field">
                           <input name="contactName" type="text" id="contactName" placeholder="Name" value="" minlength="2" required="">
                   </div>
                   <div class="form-field">
                       <input name="contactEmail" type="email" id="contactEmail" placeholder="Email" value="" required="">
                   </div>
                   <div class="form-field">
                           <input name="contactSubject" type="text" id="contactSubject" placeholder="Subject" value="">
                   </div>
                   <div class="form-field">
                        <textarea name="contactMessage" id="contactMessage" placeholder="message" rows="10" cols="50" required=""></textarea>
                   </div>
                  <div class="form-field">
                      <button type="submit" name="submit" value="send"class="submitform">Submit</button>
                      <div id="submit-loader">
                         <div class="text-loader">Sending...</div>
                              <div class="s-loader">
                                    <div class="bounce1"></div>
                                    <div class="bounce2"></div>
                                    <div class="bounce3"></div>
                                </div>
                            </div>
                   </div>

                </fieldset>
            </form>

All the messages work, am I missing out on some SMPT information or something? Are there any alternatives to using phpmailer for this job?