If you're having trouble with the app crashing or not downloading a book, the best thing to do is to delete the app and download it again from the App Store. Sorry about this!
You can also try deleting and downloading the app again if you are having trouble downloading or opening a book.
Please note that not all Leanpub books can be viewed in our app. Only books generated using the Leanpub writing and publishing workflow can be viewed in the app. If an author has made a book using their own tools and then uploaded it into our bookstore, then it cannot be read in our app.