Form mailer was working but now it doesn't

Question

I have a form on my website that has been working fine. A week or two ago it just stopped working. I have gone through it (I am not a JS/PHP expert) and it seems to verify the form but then it never gets sent.

form from the footer

<!--   beginning of form   -->
<form id="contact-form" class="contact__form" method="post" role="form" autocomplete="off" action="https://shamar.org/contact.php">

    <div class="messages"></div>

    <div class="controls">

    <!-- form element -->
    <div class="row">
      <input name="firstname" type="text" id="firstname" class="firstname1">
        <div class="col-md-6 form-group">
          <input name="name" type="text" class="form-control" placeholder="Name" required="required" data-error="Name is required.">
          <div class="help-block with-errors"></div>
        </div>
        <div class="col-md-6 form-group">
          <input name="email" type="email" class="form-control" placeholder="Email" required="required" data-error="Valid email is required.">
          <div class="help-block with-errors"></div>
        </div>
        <div class="col-12 form-group">
          <textarea name="message" class="form-control" rows="6" placeholder="Message" rows="6" required="required" data-error="Please, leave a message."></textarea>
          <div class="help-block with-errors"></div>
        </div>
        <div class="col-12">
        <input name="submit" type="submit" class="btn btn-success btn-sm" value="Send Message">
        </div>

    </div>
</form>
<!-- end form element -->

contact.php

<?php
/*
 *  CONFIGURE EVERYTHING HERE
 *  Original script: https://bootstrapious.com/p/how-to-build-a-working-bootstrap-contact-form
 *  See also /js/contact.js
 */

// an email address that will be in the From field of the email.
$from = 'mail@leeunderwood.org';

// an email address that will receive the email with the output of the form
$sendTo = 'mail@leeunderwood.org';

// subject of the email
$subject = 'Shamar Contact Form';

// form field names and their translations.
// array variable name => Text to appear in the email
$fields = array('name' => 'Name', 'email' => 'Email', 'message' => 'Message');

// message that will be displayed when everything is OK :)
$okMessage = 'Your message was sent successfully. Thank you, I will get back to you soon!';

// If something goes wrong, we will display this message.
$errorMessage = 'There was an error while submitting the form. Please try again later.';

/*
 *  LET'S DO THE SENDING
 */

// if you are not debugging and don't need error reporting, turn this off by error_reporting(0);
// error_reporting(E_ALL & ~E_NOTICE);
error_reporting(0)

try

    if(count($_POST) == 0) throw new Exception('Form is empty');

    $emailText = "You have a new message from your contact form\n=============================\n";

    foreach ($_POST as $key => $value) {
        // If the field exists in the $fields array, include it in the email
        if (isset($fields[$key])) {
            $emailText .= "$fields[$key]: $value\n";
        }
    }

    // All the neccessary headers for the email.
    $headers = array('Content-Type: text/plain; charset="UTF-8";',
        'From: ' . $from,
        'Reply-To: ' . $from,
        'Return-Path: ' . $from,
    );


    // Send email
    mail($sendTo, $subject, $emailText, implode("\n", $headers));

    $responseArray = array('type' => 'success', 'message' => $okMessage);
}
catch (Exception $e)
{
    $responseArray = array('type' => 'danger', 'message' => $errorMessage);
}


// if requested by AJAX request return JSON response
if (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
    $encoded = json_encode($responseArray);

    header('Content-Type: application/json');

    echo $encoded;
}
// else just display the message
else {
    echo $responseArray['message'];
}

contact.js

$(function () {

  // Original script: https://bootstrapious.com/p/how-to-build-a-working-bootstrap-contact-form
  // init the validator
  // validator files are included in the download package
  // otherwise download from http://1000hz.github.io/bootstrap-validator
  // See also: /contact.php

  $('#contact-form').validator();

  // when the form is submitted
  $('#contact-form').on('submit', function (e) {

//    if($('input#hnypt').val().length !=0 {
//        return false
//        }

    // if the validator does not prevent form submit


    if (!e.isDefaultPrevented()) {
        var url = "/contact.php";

        // POST values in the background the script URL
        $.ajax({
            type: "POST",
            url: url,
            data: $(this).serialize(),
            success: function (data)
            {
              // data = JSON object that contact.php returns

              // we receive the type of the message: success x danger and apply it to the
              var messageAlert = 'alert-' + data.type;
              var messageText = data.message;

              // let's compose Bootstrap alert box HTML
              var alertBox = '<div class="alert ' + messageAlert + ' alert-dismissable"><button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>' + messageText + '</div>';

              // If we have messageAlert and messageText
              if (messageAlert && messageText) {
              // inject the alert to .messages div in our form
              $('#contact-form').find('.messages').html(alertBox);
              // empty the form
              $('#contact-form')[0].reset();
              }
            }
        });
        return false;
      }
  })
});

I don't really know how to proceed as it was working before. Does anyone have any ideas of what the problem is?

(I had also tried to include a "honeypot" script but could never get it right.)

Thanks.

Lee