Pagination on custom-single.php does not work

Hello everyone, I’m here again, needing your help

I have a page “Custom-single.php” I use it to open the downloads page and view the downloads of a certain category, it shows everything right, but if it reaches the limit of 5 posting it creates pagination but it does not work when I click to move it back to the home page

someone could tell me why it does not work? is because it is a custom-single.php?

the code I’m using:

<?php query_posts($cat)?>
    <?php if (have_posts()) : while (have_posts()) : the_post(); ?>
      <ul>
	  <li><?php the_title(); ?></li>
	  </ul>
        <?php endwhile; else: ?>
		  <?php endif; ?>

       <!-- Selection end -->

    <?php if(function_exists('wp_pagenavi')) {wp_pagenavi();}?>
   </div>