if( ! function_exists( 'videotube_child_do_restrict_featured_tag' ) ){

    /**
     * Filter the WP_error
     * @param $errors
     * @param $submit_data
     */

    function videotube_child_do_restrict_featured_tag( $errors, $submit_data ) {

        // Change your featured tag name here.
        $my_featured_tag_name   =   'featured';

        if( isset( $submit_data['video_tag'] ) ){

            $video_tags =   explode(",", $submit_data['video_tag'] );

            // Check if submitted data contains the featured tag.
            if( array_search( $my_featured_tag_name, $video_tags ) !== false ){

                // add an error if tag found.
                $errors->add( "video-tag", esc_html__( 'Sorry, you cannot enter the featured tag.' ));
            }
        }

        return $errors;
    }

    add_filter( 'do_ajax_submit_video_errors' , 'videotube_child_do_restrict_featured_tag', 10, 2 );
}