Please try as below: function wp_reservations_shortcode($atts) { // remove auto paragraphs for shortcode content remove_filter(‘the_content’, ‘wpautop’); remove_filter(‘the_excerpt’, ‘wpautop’); ob_start(); ?> <section> <section class=”calendar-header”> <button id=”prev-month”>Prev</button> <div class=”current-date”>July 2024</div> <button id=”next-month”>Next</button> </section> <section class=”calendar-body”> <div class=”calendar-weekdays”></div> <div class=”calendar-days”></div> </section> </section> <?php $html = ob_get_clean(); // Re-enable automatic paragraphs add_filter(‘the_content’, ‘wpautop’); add_filter(‘the_excerpt’, ‘wpautop’); return $html; } add_shortcode(‘wp_reservations’, … Read more