This Android specific error message can appear whenever the app has trouble paginating the ebook. It can occur even if the app has previously opened the ebook without issue.
There are many reasons why this happens, but the main way to resolve the issue is to simply delete the ebook from your bookshelf and download it again. This will force repagination of the ebook and in most instances this will resolve the problem.
If the issue is not resolved there are most likely issues with the ebook file that the app cannot resolve. If you still receive the same error, then please contact our support team. Please state you have already tried the solution above. We need to know which of your ebooks is affected, and your operating system version number and your Ebook Reader app version number.
We will then test the download, and the ebook file. If the ebook has an issue we will request a corrected file from the publisher. If the ebook is not at fault then the developers then need to investigate further. This can take some time, so if at all possible we ask customers to try downloading the ebook to an alternative ebook app in the meantime.