Displaying posts of custom type based on custom taxonomy category

Hi, there! I’m trying to do something unique and I’ve struggled to find documentation that would work. Basically, I’d like to reveal a random featured photo of a custom content type, but only if it has a certain category.

I was able to get random featured photos of a custom content type to appear on the page (which you’ll see when you click the link to the page.) However, I tried to add a line that specified displaying only content from a specific category (in this case “left”). When I do this, the content no longer displays.

I think that this issue may be arising because the term “left” is a part of a custom taxonomy that I created, but I don’t know for sure. Any help would be very useful. Thank you!

function pholef() {
?>
<?php
$args = array(
    'category_name' => 'left',
    'post_type' => 'photos',
    'posts_per_page' => 1,
    'orderby'   => 'rand',
);
$the_query = new WP_Query( $args ); ?>

<?php if ( $the_query->have_posts() ) : ?>
        <?php while ( $the_query->have_posts() ) : $the_query->the_post(); ?>
            <div class="quarter">						
                <?php if ( get_the_post_thumbnail() ) : /* Show the featured image if there is one */ ?>									 
                    <?php the_post_thumbnail(); ?>
                <?php endif; ?>
            </div>
        <?php endwhile; ?>

    <?php wp_reset_postdata(); ?>

<?php endif; ?>
<?php
}
add_action('hook_top_pholef', 'pholef');

The page I need help with: [log in to see the link]