Adding a second kobo

I have been downloading library books to my kobo from my laptop.  I tried downloading books on to my husband's kobo from the same laptop and although the books transfer they will not open (message says he is not authorized with Adobe Digital Editions).  I have created a separate adobe digitals account for him.  I tried deauthorizing and still was unable to get a book to open for him.  Any help would be appreciated.  Thanks.