ACF字段的WP查询过滤器不起作用

I'm having an issue with WP query filtered by ACF Post Object Field. I have to query the 'post' filtered by 'author' acf field. i'm using this code but this don't work

$post_type_query  = new WP_Query(
    array (  
        'post_type'      => 'post',                 
        'posts_per_page' => 3,
        'meta_query' => array(
            array(
                'key' => 'author',
                'value' => 'prova'
                )
            )
        ) 
    ); 

Thereis one article on wordpress post with 'prova' author, but the query return empty. I can't understand why

Thanks

Try this:

$postData = new WP_Query(array(  
        'post_type' => 'post',                 
        'posts_per_page' => 3,
        'post_status' => 'publish',
        'meta_query' => array(
            array(
                'key' => 'author',
                'value' => 'prova',
                'compare' => '='   // or if you want like then use 'compare' => 'LIKE'
                )
            )
        ) 
    ); 

if($postData->have_posts()):
    while ($postData->have_posts()): $postData->the_post();
        echo "Post Title";
        the_title();
        echo '<div class="entry-content">';
        the_content();
        echo '</div>';  
    endwhile;
endif;