This error message is normally encountered when a user is trying to transfer ebooks from Adobe Digital Editions (on their computer) to their ADE compatible ereader device (Nook, Kobo or similar). Either the computer or the device is not authorised with an Adobe ID, or both machines are authorised with different Adobe IDs.
As a security measure both the ereader and ADE on the computer must be authorised with the same Adobe ID otherwise ADE blocks the transfer.
The solution is to deauthorise (if it has already been authorised) and then reauthorise ADE on the computer. Then once that has been done, the device needs to be connected to the computer and authorised again. Then if the book has already been downloaded it needs to be deleted and redownloaded (because the Adobe ID authentication is applied at the point of download). Finally once that has all been done if you retry the transfer it should complete successfully.
Please follow the steps on this help page to deauthorise Adobe Digital Editions.
Please follow the steps on this help page to authorise Adobe Digital Editions again.
Please follow the steps on this help page to authorise your ereader device.
If you are still receiving the error please contact our support team. Please quote the error message when doing so and the make and model of your ereader device.