WordPress: Error 404 with pagination in custom taxonomy in home

I’m having problems with pagination in a query with custom taxonomy. When I go to the second page this return me a 404 error page.

This is my code (run in index.php):

<?php
            $paged = ( get_query_var('paged') ) ? get_query_var('paged') : 1;
            $args = array(
                'post_type' => 'product',
                'posts_per_page' => 8,
                'tax_query' => array(
                    array(
                        'taxonomy'  => 'product_cat',
                        'field'     => 'slug',
                        'terms'     => array( 'destacado' ),
                        'operator'  => 'NOT IN',
                    ),
                ),
                'paged' => $paged
                );
            $loop = new WP_Query( $args );
            if ( $loop->have_posts() ) { while ( $loop->have_posts() ) : $loop->the_post(); ?>
                <li class="normal">
                    <a class="imagen" href="<?php echo get_permalink( $loop->post->ID ) ?>">
                        <?php the_post_thumbnail('thumbnail'); ?>
                    </a>
                    <a class="nombre" href="<?php echo get_permalink( $loop->post->ID ) ?>">
                        <?php the_title(); ?>
                    </a>
                    <p class="marca"><?php $terms = get_the_terms( $loop->post->ID, 'marca' ); foreach($terms as $term) { echo $term->name; } ?></p>
                    <p class="precio"><?php echo $product->get_price_html(); ?></p>
                    <span class="agregar"><?php woocommerce_template_loop_add_to_cart(); ?></span>
                </li>
            <?php endwhile; ?>

    </ul>

        <?php post_navigation(); ?>

            <?php } else { echo __( 'No products found' ); }?>
            <?php wp_reset_postdata();?>

The post_navigation() code in functions.php is:

function post_navigation() {
    echo '<div class="navigation">';
    echo '  <div class="next-posts">'.get_next_posts_link('&laquo; Older Entries').'</div>';
    echo '  <div class="prev-posts">'.get_previous_posts_link('Newer Entries &raquo;').'</div>';
    echo '</div>';
}

Thanks!