Blank Output

I get an absolutely blank page response when trying to use this in my custom theme template:

// check if the function exists
				$post_id = get_the_id();
				if ( function_exists( 'km_rpbt_related_posts_by_taxonomy' ) ) {
				  	$args = array(
						'posts_per_page' => 10,
						'exclude_terms'  => array( 12, 34 ),
					);

					$taxonomies = array( 'category', 'post_tag' );

					$related_posts = km_rpbt_related_posts_by_taxonomy( $post_id, $taxonomies, $args );

					if ( $related_posts ) {
				 		foreach ( (array) $related_posts as $related ) {

				 		?>
                        <div class="col-tn-12 col-xs-6 col-tx-6 col-sm-3 col-md-3 col-lg-4 bleed-left bleed-top gutter-bottom">

                            <?php echo '<li><a style="color:green;" href="' . get_permalink( $related->ID ) . '">' . $related->post_title . '</a></li>'; ?>

                        </div>
						<?php
                        }

					}
				}

https://www.ads-software.com/plugins/related-posts-by-taxonomy/