[Plugin: WP Easy Post Types] New Post types do not appear in Menus

I’m working on creating a site for an author. I used “Easy Post Types” to create a new post type called “Books”.

I’d like to add “Books” as part of the main navigation. However, when I go to the “menu editor” within WP, “Books” appears, but there are no items to select. See screensnap: https://www.redone.org/wp_easy-post-types.jpg

Any help would be appreciated.

Thanks,
Mike

https://www.ads-software.com/extend/plugins/easy-post-types/