Can't open a book
Can't open book I purchased. Get error message that it is formatted incorrectly and is not in a format that Apple Books can open. I have never had this problem and can not open any pot my existing books.
MacBook Pro
Assuming this is on an iPhone/iPad (posting in Books for iOS), try a force restart: Force restart iPad – Apple Support (AU)
Failing that, offload the app and download again.