Custom post types can not use the “day/name” permalink structure defined in WordPress permalinks settings. You need to add your own rewrite rules to fit your needs.
For example:
add_action('init','my_rewrite_rules');
function my_rewrite_rules(){
// Replace custom_post_type_slug with the slug of your custom post type
add_rewrite_rule( 'custom_post_type_slug/([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/(.+)/?$', 'index.php?custom_post_type_slug='.$matches[4], 'top' );
}
Note that I’ve not tested the code above. You need to flush the rewrite rules before you test it.