Problem with one with AdobeID when transferring books from library to Kobo

Hello! I am writing in regards to a message that I have been getting for a few months now, every time I try to transfer a book borrowed from a public library to my Kobo device, using Adobe Digital Editions.

I have an account with Adobe and one with Kobo, that are associated to the the same e-mail address. I have authorized ADE on my computer and connected the e-reader using the same e-mail address. However, everytime I try to transfer a book from a public library, I get the following message on my reader:

"Your eReader is not authorized to open this book. This book is protected by Adobe Digital Rights Management (DRM). You need to re-authorize your eReader with your Adobe ID using Adobe Digital Edition. Please visit help.kobo.com for more information"

I have visited the help kobo link several times and follow all possible procedures, but that didn't solve the problem. And I have tried everything so far: un-authorizing and re-authorizing ADE and Kobo device, deleting all book data from my computer, uninstalling and re-installing ADE, updating to newer version, update KOBO... nothing works. 

The only thing that worked so far was to create a whole new pair of accounts for Adobe and Kobo, and to transfer books using these new accounts. 

How can I solve the problem related to my first account and switch back to using that one?

Thank you for your assistance!