This error is most common with NOOK tablets (HD and HD+) and Kobo tablets (Arc and Arc HD), but it can also occur on other Android devices while downloading over a cellular data connection.
If you get one of these errors, reboot your device and try downloading or opening the title again. When rebooting, make sure you turn your device all the way off. Hold down the Power button until you see the power options, then select the appropriate action.
If you're still having trouble, please try downloading your title over a stable Wi-Fi connection instead.