"Not a book" error

[Ana]

Hi! I was adding a new edition of the book "The Dolphin" by Sergio Bambarén. After completing all the fields, I got the following error message:

1 error prohibited this book from being saved:
Isbn is taken by an existing book with the title "NOT A BOOK: Il Delfino". Search for 8820024381 in the header to view it. If you believe this is an error please double-check your data, then check the Goodreads Librarians group. ISBNs are optional so you can also add this book without an ISBN.

Searching for this ISBN doesn't give me any results, so how can I add the book with the ISBN, since it's the correct one?

[Scott]

This item was deemed not a book in 2017. No reason is given, so you'll have to contact support for more information.

https://www.goodreads.com/about/conta...