Wordpress form with ajax handler, white screen when button is clicked, what's wrong?

Question

JavaScript

I would like to know - I'm wrong in the code or another typo. It goes when clicking on site-name.com/wp-admin/admin-ajax.php?action=send_mail , but a white screen. In console Unchecked runtime.lastError: The message port closed before a response was received. site-name.com/wp-admin/admin-ajax.php?action=send_mail

HTML form:

<form id="pp_booking_form" method="post" action="<?php echo admin_url('admin-ajax.php?action=send_mail') ?>" >
                          <input type="hidden" id="action" name="action" value="pp_booking_mailer">
                            <input type="hidden" id="tour_title" name="tour_title" value="East Europe">
                            <input type="hidden" id="tour_url" name="tour_url" value="index.php">

                            <div class="one_half">
                                <label for="first_name">First Name</label>
                                <input id="first_name" name="first_name" type="text" class="required_field" required>
                            </div>

                            <div class="one_half last">
                                <label for="last_name">Last Name</label>
                                <input id="last_name" name="last_name" type="text" class="required_field" required>
                            </div>

                            <br class="clear">
                            <br>

                            <div class="one_half">
                                <label for="email">Email</label>
                                <input id="email" name="email" type="text" class="required_field" required>
                            </div>

                            <div class="one_half last">
                                <label for="phone">Phone</label>
                                <input id="phone" name="phone" type="text">
                            </div>

                            <br class="clear">
                            <br>

                            <div class="one">
                                <label for="message">Additional Message</label>
                                <textarea id="message" name="message" rows="7" cols="10" required></textarea>
                            </div>

                            <br class="clear">

                            <div class="one">
                                <p>
                                    <input id="booking_submit_btn" type="submit" value="Book By Email">
                                </p>
                            </div>
                        </form>

jQuery

jQuery(document).ready(function($) {
 var form = $('#pp_booking_form');
 var action = form.attr('action');

 form.on('submit', function(event) {
var formData = {
  first_name: $('#first_name').val(),
  last_name: $('#last_name').val(),
  email: $('#email').val(),
  phone: $('#phone').val(),
  message: $('#message').val()
};


$.ajax({
  url: action,
  type: 'POST',	
  data: formData,
  error: function() {
     form.html("Ваш тур не забронирован");
  };

  sussess: function() {
    form.html("Ваш тур забронирован");
  }
});

event.preventDefault();

 });
});

In functions.php it is connected like this

wp_enqueue_script( 'form_js', get_template_directory_uri() . '/assets/js/form.js', null, ['jquery'], true);

Below in the same function file is this:

add_action( 'wp_ajax_send_mail', 'send_mail' );
add_action( 'wp_ajax_nopriv_send_mail', 'send_mail' );

function send_mail() {
  $first_name = $_POST['first_name'];
    $last_name = $_POST['last_name'];
  $email = $_POST['email'];
  $phone = $_POST['phone'];
  $message = $_POST['message'];

  $to = get_option( 'admin_email');
  $subject = 'Письмо без темы';

  remove_all_filters( 'wp_mail_from');
  remove_all_filters( 'wp_mail_from_name' );

$headers = array(
  'From: Me Myself <[email protected]>',
  'content-type: text/html',
  'Cc: John Q Codex <[email protected]>',
  'Cc: [email protected]', // тут можно использовать только простой email адрес
);

wp_mail( $to, $subject, $message, $headers );
wp_die();
};

I didn't type it up, and in fact I don't know what these fields mean

<input type="hidden" id="action" name="action" value="pp_booking_mailer">
                            <input type="hidden" id="tour_title" name="tour_title" value="East Europe">
                            <input type="hidden" id="tour_url" name="tour_url" value="index.php">

But even if you comment them out, then a white screen.
Help me figure it out please!

Answer 1

Turn on the display of errors on the screen and you will see all the jambs in the script
The white screen is most likely a fatal error, which stops the execution of the script