Hello i found this code and I modified a litle, but i have a problem with it.

I want the link of the attachment page to be something like this

[post-permalink]/[gallery]/[postid] 1234/ .. /1253/

I tried this, the url is like I want to be but give me 404 error :

function wpd_attachment_link( $link, $post_id ){
$post = get_post( $post_id );
return get_permalink() . 'galery/' . $post->ID ;
}
add_filter( 'attachment_link', 'wpd_attachment_link', 20, 2 );

How to do that ?

Thank you