Previously deauthorized message

After having to deauthorize and authorize my kobo aura many times,  I received a message telling me I had too many devices on my account and so started a chat.  Eventually, the agent understood that i only had one kobo aura that i had to keep reauthrorizing and they fixed my account so i could activate again.

When I try to download books now, i get another message telling me :  This book is protected by ADRM, because you previously deauthroized your eReader, you need to reimport the book using ADE.

I have tried downloading new books and get the same message, even though they were borrowed from library and downloaded after i reauthorized my eReader.