Show Form On Event Calendar Plugin's Single Event Page Only

I’m attempting to show a Contact Form 7 form using a shortcode with Modern Tribe’s Event Calendar on their single event page only. I’ve tried using the following, but none are working.

<?php 
  
   if (is_page('specific-page')) { //this page is where the calendar sits
        echo do_shortcode('
Error: Contact form not found.
');
           } else {
           //do nothing else    
      }
 ?>

And then I tried this. Custom Post Type. Although Event Calendar is a CPT I’m not sure their parent page is and or the children beneath the parent.

<?php
 
   $page = get_post();
      if ( is_singular('What_Goes_Here?') && $page->post_parent > 0 ) {
          // This is a custom post type subpage
           echo do_shortcode('
Error: Contact form not found.
');
             } else {
          // This is not a custom post type subpage
    }
?>

Neither works. And I’m not 100% sure on the Custom_Post_Type one. I did change the default page name from Events to Custom Events for calendar page and Custom-Event for single event page. So the url is example.com/custom-event/whatever-is-going-on-that-day.

I need the form to only show on any sub page of custom-event. Not sure how to go about this. Thanks.