Remove YARPP meta-box in post and page editing

I’m running a multisite network and I’d like to hide the YARPP meta-box in post and page editing.
I’m using the Genesis framework.
I tried this on a subsite:

function remove_post_custom_fields() {
	remove_meta_box( 'postcustom' , 'post' , 'normal' );
	remove_meta_box( 'yarpp_relatedposts' , 'post' , 'normal' );
}
add_action( 'admin_menu' , 'remove_post_custom_fields' );

It does remove the custom post field meta box but not the yarpp box. Don’t understand why.
Any idea?
Thanks!

https://www.ads-software.com/plugins/yet-another-related-posts-plugin/