WP_Query with meta_query won't orderby

Question

I get the posts but they are not sorted by 'sort' values. What's wrong with the following code?

$args['meta_query'] = array(
    'relation'  => 'AND',
    'cast'      => array( 
        'key'       => 'cast',
        'value'     => $cast, 
        'compare'   => 'LIKE'
    ),
    'director'  => array(
        'key'       => 'director',
        'value'     => $director,
        'compare'   =>'='
    ),
    'sort'      => array(
        'key'       => 'score',
        'compare'   =>'EXISTS'
    ) 
);
$args['orderby'] = array( 'sort' => 'DESC' );

Answer 1

Problem Fixed!

there was an issue in input of post_meta_field.

after updating post, problem fixed.