When a store rejects your ebook
The email is short. It arrives some time after you upload — how long differs by store and changes, and What happens to your file after you upload it explains which stage it came out of — it names one reason, and it does not explain it.
The first thing to understand is who wrote it. That message was assembled from a list of standard reasons so it could be sent quickly to thousands of people. Nobody sat down and looked at your book and wrote you a note about it. The reason it names is a category, picked because your file landed in it, and your job is to read it as a pointer to where to look rather than as a description of what is wrong.
That reframing matters, because authors lose days arguing with the literal words of a message that was never precise. The message tells you the neighborhood. You still have to find the house.
The categories, and what actually sits behind them
The file fails validation. Something in the EPUB is structurally wrong: a file listed in the manifest that is not in the package, an image or link pointing at a name that does not exist, a navigation document that does not match the real chapters, missing or malformed metadata such as the identifier or the language. This is the one to rule out first, because it is the only category that is fully objective — the file either conforms or it does not, and the failure comes back as a line-by-line report you can act on. What makes an EPUB pass validation covers what those checks look for.
The cover. Usually the dimensions or the resolution: a cover far off the proportions the store wants, or one that is technically the right shape but built from an image too small to hold up at the size it will be shown. A second version of this problem is a cover that does not match the listing — a different title on the image than in the title field, a subtitle or a series number that appears in one and not the other.
Metadata mismatch. The title and author stored inside the EPUB disagree with the fields you typed into the upload form — two separate sets of fields, which is the whole subject of The metadata inside your ebook file. Both are correct on their own; they just do not agree. Stores treat that disagreement as a quality signal, because it is usually a sign that the file was made for something else — a different edition, a different pen name, a title that changed late and was only changed in one place.
Duplicate content. The book looks to the store like something already in the catalog. The uncomfortable version of this is that the something is often your own earlier upload: a second attempt made while the first is still pending, a file that reuses an identifier, or a new edition that reads as a copy of the old one rather than a replacement.
Links. The store objects to where something in your book points. This is worth checking even when you think you have no links, because back matter and copyright pages collect them.
Formatting broken enough to be caught automatically. Not "I dislike your typeface" — that is not what automated checks look at. This is text that fails to render, pages that come out empty, a body that is one continuous block with no chapter structure, or images that do not display.
In the Interior Formatter. The EPUB 3 it builds validates with zero errors and zero warnings under epubcheck, and carries the title, author and language from your book's own fields — which removes the largest rejection category before you upload. Start your ebook → · about the Interior Formatter
Work in this order
Validate the file yourself before you assume anything. Do this even when the message says nothing about validation, and before you touch the cover or the listing. It is the cheapest check you have and the only one that gives you a definite answer. If the file is clean, you have eliminated a whole category and you can stop guessing about it.
Compare the file's internal metadata against the listing fields. Put them side by side: title, subtitle, author name and spelling, series name and number, language. Read them as strings, character by character. "J. A. Smith" and "J.A. Smith" are a mismatch.
Check the cover's size and resolution. Confirm its pixel dimensions and its proportions, and confirm the title on the image is the title on the listing. An ebook cover is a separate file at separate proportions from your print front, which Ebook cover size, and why it is not your print front sets out.
Then change one thing and resubmit. This is the discipline most authors skip. Fixing five things at once and uploading again means that if it is rejected a second time you have learned nothing, and if it is accepted you still do not know which fix mattered — so you will hit the same wall on your next book. One change, one resubmission.
What nobody can tell you in advance
Each store runs its own checks, sets its own limits, reviews on its own timetable, and has its own way of handling a repeat problem or a dispute. Those rules differ between stores and change without announcement, so any specific figure you read in an article — including this one — is a guess about someone else's business.
So read the actual message you were sent, then read that store's own help page for the reason it names. Those two documents are the only authoritative sources here. Everything above is a map of where to look while you read them.
Make your ebook
The tools are free to use: bring your manuscript once and get both a print PDF and an EPUB out of the same source, so the two editions cannot drift apart. You only pay when you want the files without the preview watermark.
Next: Updating an ebook after it is published · More: What makes an EPUB pass validation · Checking an ebook before you publish it · Uploading your files for the first time