ISBN already in use
The error “ISBN already in use” appear when there is another book with the same ISBN. This includes books that are drafts or delisted from sale. Once an ISBN is entered, it cannot be changed and cannot be used again for another book.
If you already have a draft or a delisted book using the ISBN, please go back to your original draft and continue the publishing process there so you can reuse the ISBN.
You can also click “publish” without listing an ISBN and a Kobo-specific ID will be assigned to the book, which cannot be changed later.
100MB Error Help:
The file size for your book (including images) cannot exceed 100MB.
You may be able to reduce the size of the file by doing the following:
- Compress Images: Use image editing software to adjust the size or reduce the resolution of the images within the EPUB.
- Remove Unused Images: If there are any images in the EPUB that are not being used in the text remove them.
- Compress file: Use an EPUB compression tool to compress your EPUB file while maintaining its integrity.