Php error after adding php code

Hallo, nice to meet you

When I was adding php code in code snippet plugin, my website have error and crash. Here is the error log

Parse error: syntax error, unexpected token “endif” in /home/xxxx/public_html/wp-content/plugins/code-snippets.ol/php/snippet-ops.php(504) : eval()’d code on line 47

And here is the php code that I was adding

// Related Post Berdasarkan Kategori
add_action( 'generate_before_comments_container','langit_related_post' );  
function langit_related_post() { 
	if ( is_single() ) : ?>
<div class="related-post__container">
	<h2 class="related-post__header">Related Posts</h2>
	<div class="related-post__content">
		<?php
            global $post;
            $orig_post  = $post;
            $categories = get_the_category($post->ID);
            
                if ($categories) {
                $categories_ids = array();
                foreach($categories as $individual_category) $category_ids[] = $individual_category->term_id;
                $args=array(
                'category__in'        => $category_ids,
                'post__not_in'        => array($post->ID),
                'posts_per_page'      => 3, // Number of related posts to display.
                'ignore_sticky_posts' => 1
                );
                
                $related_query = new wp_query( $args );
                
                while( $related_query->have_posts() ) {
                $related_query->the_post();
                ?>

		<div class="related-post__item">
			<div class="related-post__item--thumb">
				<a rel="nofollow" href="<? the_permalink()?>"><?php the_post_thumbnail(array(300,150)); ?>
				</a>
			</div>
			<h3 class="related-post__item--title">
				<a href="<? the_permalink()?>"><?php the_title(); ?></a>
			</h3>
		</div>

		<? }
  }
  $post = $orig_post;
  wp_reset_query();
  ?>
	</div>
</div>
<?php 
	endif;
}