Why Your EPUB Gets Rejected by Kobo (But Not KDP)
If your ebook passed Amazon KDP but failed on Kobo, this guide explains why platform checks differ and how to fix rejection issues fast.
It’s one of the more baffling moments in self-publishing. Your book is live on Amazon, readers are buying it, and everything seems fine. Then you upload the very same file to Kobo, and it’s rejected.
It’s natural to assume Kobo is being difficult, or that something is wrong with your book. Usually neither is true. The same EPUB is simply being treated in two quite different ways, and once you understand the difference, the fix is normally straightforward.
Why the same file passes one store and fails another
The key difference is what each store does with your file. When you upload an EPUB to KDP, Amazon converts it into its own Kindle format. That conversion is forgiving: plenty of small technical flaws are smoothed over along the way, and you never see them.
Kobo works much closer to the file you actually made. It checks your EPUB against the EPUB standard far more strictly, because in many cases that’s very nearly the file it will deliver to readers. Problems Amazon’s conversion quietly absorbed are suddenly visible.
So a Kobo rejection usually isn’t a new problem. It’s an existing one that Amazon happened to tolerate. That’s worth knowing, because it means fixing it improves your book everywhere, not just on Kobo.
What the error messages are really telling you
Kobo’s rejection messages often sound alarming and technical, mentioning navigation that can’t be read, resources that can’t be found, or problems with the package. Almost none of them are about your writing. They point to how the file is put together: the table of contents, the links between files, the images, and the information describing the book.
Read the message closely, because it usually names the area, and sometimes the exact file, that needs attention. Then work through the common causes below.
The usual suspects
1. Navigation and heading structure
Kobo is less forgiving than Amazon about a messy table of contents or inconsistent headings. A chapter that uses a different heading level from the others, a contents entry that points to a section that no longer exists, or a table of contents typed out as plain text can all cause a rejection.
The fix is to give every chapter the same heading style and rebuild the table of contents from those headings, then click through it to make sure each entry lands where it should.
2. Old styling carried over from earlier tools
Books that started life in Word, or passed through several conversion tools over the years, tend to accumulate old CSS and inline styles. Amazon’s conversion ignores much of it. Kobo may not, and the result can be a rejection or chapters that display oddly on Kobo devices.
Rather than hunting through the code, it’s usually quicker to rebuild the styling as one clean, consistent set of rules and export a fresh file.
3. Metadata that doesn’t add up
Every EPUB contains details about itself: the title, author, language and a unique identifier. If any are missing, or don’t match each other, Kobo is more likely than Amazon to object. Check them carefully and re-export afterwards, so the file’s internal records are regenerated, not edited by hand.
4. Images the file can’t find
If the book refers to an image that isn’t where the file says it is, Amazon may simply drop it during conversion while Kobo flags it as an error. Make sure every image is actually included in the file, re-add anything that’s missing, and export again.
How to fix it without making things worse
When a rejection arrives, resist the urge to change everything at once. Start with the specific message, then check navigation and headings first, since they’re the most common cause. Look at styling and images next. Make one set of fixes, export a clean file, and upload again. If you change five things at the same time and the upload succeeds, you’ll never know which one mattered, and if it fails, you won’t know which change made it worse.
If the book is an older title from your backlist, it’s often faster to import it into a formatting tool and rebuild it cleanly than to patch the old file. How to Import an Old EPUB and Clean Up Messy Formatting covers that approach.
Preventing it next time
The authors who rarely see rejections tend to work the same way: they keep one clean source for each book and produce a fresh file for every store from it, rather than keeping several slightly different copies and editing each one by hand. Consistent headings from the start, no leftover formatting tricks, and a quick check before every upload do most of the work.
That’s the thinking behind Libba’s per-store exports. You keep one project, and Libba produces a separate EPUB for Kobo, Kindle, Apple Books and the others, each built fresh with the links that store allows. Format Once, Publish to Kindle, Kobo, and Apple Books explains the workflow in more detail.
Common questions
My file passes EPUBCheck. Why is Kobo still rejecting it? EPUBCheck confirms the file meets the EPUB standard, but each store also has its own requirements on top of that. Passing EPUBCheck makes a rejection much less likely, but it isn’t a guarantee.
Should I keep a separate version of my book just for Kobo? Usually not. Fix the problem once in your source and export fresh files for every store. Separate hand-edited copies tend to drift apart over time.
Does a Kobo rejection mean my book is broken everywhere? Not necessarily. More often it means Kobo noticed a structural issue that other stores tolerated. Fixing it makes your book more robust on every platform.
If Kobo has rejected a file Amazon accepted, the answer is almost always structural tidying, not rewriting your book. For the Amazon side of the story, see Why Your EPUB Gets Rejected by KDP (And How to Fix It).
