Book Corrupt

Hi!

I downloaded a free book from my favourite author in iBooks. I then synced my iPad to my iMac.

Went to open the book on my iPad and got the message that the book was corrupt. Tried opening the book in iBooks on the iMac and got the same message.

Tried deleting the book and re-downloading but still get the same message.

Any ideas on what to try next?

Buff