wordpress get_terms function not working in my plugin
$terms = get_terms($taxonomy , 'hide_empty=0');
print_r($terms);
$count = count($terms);
if ( $count > 0 ){
echo "<ul>";
foreach ( $terms as $term ) {
  echo "<li>" . $term->name . "</li>";

}
echo "</ul>";

WP_Error Object
(
    [errors] => Array
        (
            [invalid_taxonomy] => Array
                (
                    [0] => Invalid Taxonomy
                )

        )

    [error_data] => Array
        (
        )

)

function load_terms($taxonomy){
    global $wpdb;
    $query = 'SELECT DISTINCT
                                t.name
                            FROM
                                `wp-cls`.wp_terms t
                            INNER JOIN
                                `wp-cls`.wp_term_taxonomy tax
                            ON
                             `tax`.term_id = `t`.term_id
                            WHERE
                                ( `tax`.taxonomy = '' . $taxonomy . '')';
    $result =  $wpdb->get_results($query , ARRAY_A);
    return $result;
}