404 error after publishing the flipbook

The preview works fine but when I publish the book and click on the “See FlipBook” I get a 404 page not found error.

The url is https://xxxxxxxxx.com/flip_pong/booklet

I also created created a category called flip_pong but that didn’t work either.

Any help would be appreciated. Otherwise it’s a very nice plugin.

https://www.ads-software.com/extend/plugins/flip-pong-v/