wordpress related posts

<?php
   //for use in the loop, list 5 post titles related to first tag on current post
   $categories = get_the_category();
   $category_id = $categories[0]->cat_ID;
   if ($category_id) {
       $args = array(
          'cat' => 2, -1,
          'posts_per_page' => 6,
          'orderby' => 'rand',
       );
       $my_query = new WP_Query($args);
       if ($my_query->have_posts()) {
           while ($my_query->have_posts()): $my_query->the_post();?>
			<div class="col-6 col-sm-4">
				<a class="" href="<?php the_permalink()?>">
					<div style="max-height:195px; overflow: hidden;" class="blockHover">
						<?php
    if (has_post_thumbnail()) { // check if the post has a Post Thumbnail assigned to it.
        the_post_thumbnail('full', array('class' => 'img-fluid products-img')); // show featured image
    }?>
					</div>
				</a>
				<a class="" href="<?php the_permalink()?>">
					<h5 class="text-uppercase text-center mt-2 lead">
						<?php the_title();?>
					</h5>
				</a>
			</div>
			<!-- col -->
			</a>
			<?php
   endwhile;
       }
       wp_reset_query();
   }
   ?>