Query Posts by Tag and exclude

It seems you’re looking for the tag parameters:

$args = array(
    'posts_per_page' => 5,
    'tag' => 'YOUR-TAG-SLUG',
    'orderby' => 'date',
    'order' => 'DESC',
);
$query = new WP_Query($args);
while ($query->have_posts()) :
    $query->the_post();

    ...

endwhile;
// don't forget to reset/restore the query
wp_reset_postdata();

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