If you get an error message that starts with E_ADEPT_REQUEST_EXPIRED when you are trying to authorize your computer or device with Adobe Digital Editions, or when you are trying to download in ebook, here is the likely solution.

If you are travelling, make sure you set the clock, calendar and time zone on your computer or device to the location that you are currently in.

If you are at home, make sure that the clock and calendar on your computer are set correctly, and that you have selected the correct time zone.

Doing this should resolve the issue.