I get the same thing. I have reset my Kobo to factory setting. Checked my Adobe Digital account to make sure I have correct ID and password. I have unauthorised the account in Kobo and then authorized again. My e-books are current from the library. When I try and drag them in I get CE_COPY_NOT_ALLOWED. I hope someone can help.
Has you used the same Adobe ID for Device and PC?
If yes, check if you can copy the eBook. Any eBooks from Library could not copy.