Sorting Posts By Comment Count NOT WORKING

Is there a reason why posts dont get sorted by comments? I have tried and tried just not working. I have the Jetpack comments enabled so could this be the problem??

I have pasted the custom page template so you guys can see because i’m stomped

<?php
/*
  Template Name: Popular Posts
*/

get_header();

$paged = ( get_query_var('paged') ) ? get_query_var('paged') : 1;

// WP_Query arguments
$args = array (
	'post_type'              => array('post'),
	'pagination'             => true,
	'posts_per_page'         => '12',
	'order_by' 				 => 'comment_count',
	'order'					 => 'DESC',
	'paged'					 => $paged,
	'ignore_sticky_posts'	 => true,
);

$orig_post = $post;

// The Query
$wp_query = new WP_Query( $args );

// The Loop
if ( $wp_query->have_posts() ): ?>
<div class="articles-list">
	<div class="list-em">
		<div id="articles-container">
		<?php while ( $wp_query->have_posts() ): $wp_query->the_post(); ?>

		<?php
			/* Include the Post-Format-specific template for the content.
			 * If you want to override this in a child theme, then include a file
			 * called content-___.php (where ___ is the Post Format name) and that will be used instead.
			 */
			get_template_part( 'content', get_post_format() );
		?>

		<?php endwhile; ?>

		<?php $post = $orig_post ?>

		<?php the_posts_navigation(); ?>

		</div>
	</div>
</div>
<?php else: ?>

	<?php get_template_part( 'content', 'none' ); ?>

<?php endif; ?>

<?php wp_reset_postdata() ?>
<?php // wp_reset_query() ?>
<?php get_footer() ?>