WooCommerce sort by SKU

To use with woocommerce plugin and theme already css and code.

$args = array(
            'post_type'      => 'product',
            'post_status'    => 'publish',
            'posts_per_page' => -1,
            'meta_key'       => '_sku',
            'orderby'        => 'meta_value',
            'order'          => 'DESC',
          );
query_posts( $args );
if( have_posts() ) :
  while (have_posts()): the_post();
    wc_get_template_part( 'content', 'product' );
  endwhile;
endif;
wp_reset_query();

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)