Just recently this error (normally followed by another error "Something went wrong") has been occurring due to a compatibility issue with the latest update of Android 9.0 (Pie) and Ebook Reader 18.104.22.168. Please update the Ebook Reader app to the recently released newer version and this should resolve the issue. (You may need to uninstall and reinstall the app)
Otherwise, this error message can normally occur if your are running an older version of Android, or you have an older version of the Ebook Reader app. It can also occur if you purchase multiple ebooks and try to download them all at once.
First please check if any updates are available for your operating system and install them if there are. Then check if there are any updates for the app and update it if there are.
Then please do the following:
* Open the Ebook Reader app on your device
* Go to Settings and log out of the app
* Then log back in to the app
* Wait until the box pops up showing your latest purchases and select the new ebook (please only select one ebook), then select "Download selected"
* Wait for the download to finish and for the cover to appear in your bookshelf before opening
If this doesn't work please contact our support team. Please quote the error message, state which ebook (or ebooks) in your account you are unable to download and please also state your operating system version number and Ebook Reader app version number.