Enable to read borrowed book : problem between Kobo and ADE

I used to borrowed books from my library.  This time around it is not working.  Got the message (translated to English here from French) : This book is protected.  Becuase you have desauthorized your reader you have to reimport the book by using ADE.  I tried EVRYTHING found here in this community, and elsewhere in the internet : Desauthorised my computed, my e-reader, uninstalled ADE on my computer, brought back my e-reader with factory settings, and reconfigured all this.  Tried Many time.  Even had a chat with Kobo support who made me do the same things again.  NOTHING WORKS.  Please!! I'm going CRAZY!!