only_on not working?

I am trying to show a meta box only on a specific page. I posted about this on the git page and they said to use.

'only_on'    => array(
		'id'       => array( 1, 2 ),
		'slug'  => array( 'news', 'blog' ),
		'template' => array( 'fullwidth.php', 'simple.php' ),
		'parent'   => array( 10 )
	),

However this does not seem to be working. I did change those values to the values I wanted and tried only using slug with the page slug etc and what ever I do it will not show up on that page or any page. I can only get it to show up if I use page ‘pages’ => array( but then it shows on all pages etc.

https://www.ads-software.com/plugins/meta-box/