links don't work

No siblings appear at the top level, but the page I’m on appears with child pages. That’s OK, since I want the child pages, and I have the top level pages in the menu on top. I only have pages one level deep. Rather than the link, “http://reasonthebook.com/excerpts/assumptions/,” the links go to links like, “http://reasonthebook.com/?page_id=1752.” They don’t resolve. The generated menu also contains the parent page, which is perfect, but not expected.

https://ww.wp.xz.cn/plugins/sibling-pages/