Send alert when new tag final

function send_alert_when_new_tag( $term_id, $tt_id, $taxonomy ) {

    global $post_id;
    $post_title   = get_the_title( $post_id ); // retrive the post tile
    $post_url     = get_permalink( $post_id ); // retrive the post url
    $author       = get_post( $post_id );      // gets author from post
    $author_id    = $author->post_author;      // gets author id for the post
    $author_name  = get_the_author_meta( 'display_name', $author_id ); // retrive display name
    $current_user = wp_get_current_user();     // retrive current user
    $tag_url      = get_bloginfo( 'url' ).'/wp-admin/edit-tags.php?taxonomy=article_tags&post_type=article'; // tag url
    $subject      = 'Alerta de tag creado por: '.$current_user->display_name;
    $tag          = get_term_by( 'id', $term_id, $taxonomy );
    $to           = array( '[email protected]', '[email protected]', '[email protected]', '[email protected]' );

    $message      = 'Tag creado:'. $tag->name ."\n\n";
    $message     .= 'Título del artículo: '.$post_title."\n\n";
    $message     .= 'Usuario: '.$current_user->display_name."\n\n";
    $message     .= 'Author: '.$author_name."\n\n";
    $message     .= 'Url del artículo: '.$post_url."\n\n";
    $message     .= 'Url de tags: ' . $tag_url;

    // Send test email
    wp_mail( $to, $subject, $message );

    }

    // Notify when new tag is created
    add_action( 'created_term', 'send_alert_when_new_tag', 10, 3 );