cannot copy book

Long time ago, I installed adobe digital edition and I rent epub books farom my local library, then copy it on my kobo reader.  months ago I had to  clear all my laptop and reinstall everything.  Last week I tried to copy a book on my kobo reader and sais it sais 'not autorized to copy'.  I followed instructio ns to authorize bot my laptop and reader, but I still get the error message.  Can somebody help me ?