I authorized my kobo with digital editions. When I put a library book onto the kobo, I got the message- This document is protected by Adobe Digital Rights Management and is not currently authorized for use with your Adobe ID. Please sign in with the authorized Adobe ID and try again
If you are trying to transfer a library book from your computer to your Kobo, then both have to be using the same authorisation.
I had same problem on my Mac and Kobo, and the following worked for me. If you use an IBM, then finding and deleting the same activation.dat file will work.
The computer needs to be authorised first with the reader disconnected, then deauthorise your Kobo, connect to your computer, and then reauthorise your Kobo with the computer.
A few months ago I changed my Adobe ID and password. Fast forward to now and I'm having the same prob as everyone else. Here's what worked for me:
1. Go to the Finder menu.
2. Hold down the Option key and select Go. This reveals the hidden user library.
3. Select Library.
4. Go to Application Support -> Adobe -> Digital Editions and delete the file named “activation.dat”
5. Now one can reauthorize Adobe Digital Editions.