I populated the author, genre, and publisher fields and they are all coming back with 404 errors. The review shows up. I also did a new test review and it has the same issues. https://childrensreadinglist.com/reviews/test-review/
I am having the same issue as @vfenix. I have the error on the setting page “You’ve set up everything correctly here but now WordPress is giving you an 404 (not found) error? Try flushing your permalink settings. Visit Settings -> Permalinks and just save without changing anything.”