load more ajax post

function more_post_ajax(){

    $ppp = (isset($_POST["ppp"])) ? $_POST["ppp"] : 9;
    $page = (isset($_POST['pageNumber'])) ? $_POST['pageNumber'] : 0;

    header("Content-Type: text/html");

    $args = array(
        'suppress_filters' => true,
        'post_type' => 'post',
        'posts_per_page' => $ppp,
        'paged'    => $page,
    );

    $loop = new WP_Query($args);

    $out = '';

    if ($loop -> have_posts()) :  while ($loop -> have_posts()) : $loop -> the_post();

         $thumb2 = wp_get_attachment_image_src( get_post_thumbnail_id(), 'full' );
         $out .= '<div class="col-xl-4 col-lg-4 col-md-4 col-sm-12 col-xs-12 blog-item-wrap">
              <a class="post-list-item" href="'.get_the_permalink().'">
                  <div class="post-list-item-wrapper">
                    <div class="item-post-thumbnail">
                       <img class="lazyload" data-src="'.$thumb2[0]. '">
                    </div>
                    <div class="item-post-content">
                        <h2>'.get_the_title().'</h2>
                        <span class="post-date">'.get_the_time('j F Y').'</span>
                        <p>'.wp_trim_words( get_field('introduce_text'), 15 ).'</p>
                    </div>
                  </div>
               </a>
          </div>';

    endwhile;
    endif;
    wp_reset_postdata();
    die($out);
}


add_action('wp_ajax_nopriv_more_post_ajax', 'more_post_ajax');
  add_action('wp_ajax_more_post_ajax', 'more_post_ajax');