I am trying to trasfer abook from Digital Editions to my ereader. I keep getting a notice that I am not authourized to copy this book. I have tried cacelling my authourization and re authourizing but that doesn't work Any Ideas?

I am trying to transfer a book from Adobe Digital Editions to my ereader.  I keep getting a notice that I am not authorized to copy the book.  I checked Forums and eraced my authorization and reauthorized.  Nothing seems to work.  I used Digital Editions 3 and never had a problem but this edition 4 I am having problems.  Can anyone help?