Remove Meta box on posts

Hi, how to remove the meta box? I only want to use the widget. I tried this code from www.remarpro.com, but it doesn’t affect it:

add_action( 'do_meta_boxes', 'remove_plugin_metaboxes' );
function remove_plugin_metaboxes(){
		remove_meta_box( 'simple-related-posts', 'post', 'normal' );
}