Thanks to you.
The universal scenario when you don’t know what capability protects custom post type, look for that using Admin menu access add-on. Open it for ‘Administrator” role and look what capability protects needed menu item. Grant that capability to the selected role then. If this is a ‘edit_posts’, but you don’t need that this role access to the posts, except ‘nieuws’, then block unneeded menu items, like ‘Posts’ menu with the same “Admin menu access” add-on.