Why Your Book Got Rejected & How to Fix It
You spent months writing your book. You formatted it, built the cover, hit publish — and got a rejection email. Or worse: it went live, and a reader messaged you about garbled text on their Kindle.
Neither of these problems has anything to do with your writing. KDP and Apple Books reject books almost entirely for technical reasons: broken file structure, missing metadata, invalid XML, cover images that don't meet spec. These mistakes are invisible in Word and catastrophic on a publishing platform.
This guide covers every major rejection category, what the actual error messages look like, and the exact fix for each one. By the end, you'll know how to catch these problems before you upload.
The Two Types of Rejection
Before diving into specific causes, it's worth understanding the difference between the two types of rejection — because they need different responses.
Hard technical rejections block your upload entirely. You get an error within minutes of submitting. The book never enters the publishing pipeline. These are actually the easier type to fix: the error is immediate, specific (even if vague-sounding), and completely preventable with pre-upload validation.
Soft failures are worse. Your book gets accepted, it goes live, and then readers on certain devices see formatting problems — garbled characters, a missing table of contents, images that don't display, chapters that run together. You might not find out for weeks. These come from the same source as hard rejections: a file that wasn't properly formed. But because Amazon converts your EPUB before delivery, it accepts files that will break on delivery.
Both types are preventable. The fix is the same: validate your file against the spec before you upload anywhere.
EPUB Structure Errors
These cause the majority of hard rejections. Your EPUB is a ZIP archive with a strict internal structure. If that structure is wrong, neither KDP nor Apple Books can read the file — regardless of how good the content is.
Broken or Missing Mimetype File
Every EPUB must contain a file called mimetype as the very first entry in the ZIP archive. It must be stored without compression, and it must contain exactly the text application/epub+zip — no trailing newline, no extra whitespace.
KDP error message you'll see:
"Your file could not be uploaded. The file format is invalid
or the file is corrupt. Please check that you have uploaded
the correct file type."This is one of the most common causes of immediate rejection, and one of the most fixable. The problem usually comes from how the EPUB was packaged — most standard ZIP tools compress the mimetype file, which breaks it. The fix is to repackage using an EPUB-aware tool, or use a command-line ZIP tool with the -X flag to store the mimetype without compression.
Missing or Invalid Table of Contents
Every EPUB needs a navigable table of contents. EPUB 3.0 requires a nav.xhtml navigation document with a <nav epub:type="toc"> element. EPUB 2.0 requires an NCX file. If both are missing, or the links inside point to files that don't exist, KDP blocks the upload.
KDP error:
"No table of contents (TOC) found. Please include a TOC
in your file to help readers navigate your book."Apple Books rejection:
"Your book's table of contents could not be detected.
Please ensure your EPUB contains a valid navigation document."The EPUB Validator identifies exactly which TOC element is missing. If the TOC is irreparably broken, the TOC Generator rebuilds a valid one from your chapter headings in a few seconds.
Invalid XHTML in Chapter Files
EPUB chapter files must be valid XHTML — not HTML, not HTML5, but XHTML. This is stricter than what browsers accept. Every tag must close, attribute values must be quoted, and the document must be parseable as XML.
Common violations:
<br>instead of<br/><img src="...">instead of<img src="..."/>- Bare
&in text (must be&) - Smart quotes or em dashes that didn't encode as UTF-8
- Missing
xmlnsattribute on the root<html>element
One unclosed tag in one chapter file is enough to fail the whole upload. Run the EPUB Validator to get exact filename and line number for every XHTML error — then fix each one before uploading.
Malformed OPF Manifest
The OPF file is the index of your entire EPUB. It lists every component: chapter files, images, fonts, stylesheets. If a file listed in the manifest doesn't exist, or a file that exists isn't in the manifest, KDP rejects the upload.
KDP error:
"Your book file contains errors. One or more files referenced
in the manifest do not exist."Open your OPF file in a text editor and compare the manifest item list against the actual files in your EPUB folder. Remove entries for non-existent files. Add entries for files that exist but aren't listed. Every file path must be an exact relative path, case-sensitive.
Metadata Errors
Metadata errors are trickier because they often don't cause a hard rejection — they cause a soft failure or a mismatch between your EPUB and your platform listing that creates an ingestion error after the file is accepted.
Missing or Malformed Title and Author
Your OPF file must include a dc:title and a dc:creator element in the metadata block. If either is missing, or the value is blank, platforms flag it during ingestion. The title and author in the OPF must also match what you enter in KDP or Apple Books Connect — mismatches trigger separate errors even when the file itself validates cleanly.
Wrong Language Code
The dc:language tag must use a BCP 47 language code — en or en-US, not the word "English". Apple Books is strict about this. A dc:language value of "English" instead of "en" causes a metadata rejection. This is a one-character fix with significant consequences if you miss it.
Cover Image Not in Manifest
Your cover image must be listed in the OPF manifest with the correct properties="cover-image" attribute. If the cover isn't in the manifest, or isn't flagged as the cover image, platforms may accept the file but display a generic placeholder instead of your cover — which affects your book's appearance in every store and search result.
The correct manifest entry:
<item id="cover-image" href="images/cover.jpg"
media-type="image/jpeg"
properties="cover-image"/>For cover dimension requirements by platform - minimum pixel size, ideal dimensions, and aspect ratio - see the book cover size guide.
Why KDP Accepts Files Apple Books Rejects
This is the most confusing scenario: you upload to KDP, it goes live, everything seems fine. You upload the same file to Apple Books and get a rejection email.
The reason is fundamental to how each platform works. KDP converts your EPUB into its own internal format before delivery. During that conversion, it silently fixes or ignores many structural problems — unclosed tags, missing metadata, malformed OPF entries. Amazon has built a forgiving converter because it transforms every file anyway.
Apple Books delivers your EPUB directly to iOS and macOS devices as-is. Every HTML error, every OPF problem, every CSS issue reaches the reader's device. Apple validates strictly because it can't silently fix problems that will break the reading experience on hardware it doesn't control.
If your EPUB has structural problems, Amazon hides them from you. Apple doesn't.
Apple Books: External CSS and Fonts
Apple Books blocks all external resource loading at the system level. If your CSS contains any @import url() pointing to an external stylesheet or font service — including Google Fonts — Apple rejects the file. All fonts and stylesheets must be embedded inside the EPUB package. No CDN fonts, no remote CSS, no external images loaded via CSS background-image.
Apple Books: EPUB 2 vs EPUB 3
Apple Books technically accepts EPUB 2.0, but many EPUB 2.0 files fail because they were created by tools that weren't strict about spec compliance. EPUB 3.0 is what Apple Books is optimized for. If you have an EPUB 2.0 file that keeps getting rejected, rebuilding it to EPUB 3.0 spec is faster than trying to patch all the individual 2.0 issues. The EPUB Formatter converts your manuscript directly to EPUB 3.0 spec.
Cover Image Rejections
Cover image errors are common and easy to miss — most authors check their cover visually, not technically.
Cover Too Small
KDP requires a minimum cover size of 2,560 × 1,600 pixels. Apple Books requires 2,400 × 1,600. A cover smaller than these dimensions gets rejected before your book goes live. The file must be a JPEG or TIFF under 50MB. Run the Cover Checker to verify your cover against all platform requirements in one step.
Interior Images Too Large
High-resolution images from photography or print design are almost always too large for ebook delivery. Apple Books enforces a 2MB limit per interior image and a 4MB limit per cover. Images over those limits cause rejections — often with a vague error that doesn't mention image size at all. Resize interior images to 96 DPI and compress before embedding. JPEG at 85% quality at 96 DPI is the right target.
Wrong Image Format
Apple Books doesn't reliably support WEBP images. If your EPUB contains WEBP files, convert them to JPEG or PNG before embedding. WEBP may display correctly on some devices and fail on others — which puts you in the worst category: a book that passed validation but breaks for some readers.
Content Policy Rejections
Not all rejections are technical. If your book clears structural validation but gets rejected after 24–72 hours, it's likely a content policy issue.
Content rejections are categorically different from technical rejections:
- Technical errors are flagged within minutes of upload
- Content violations appear after the file enters content review — usually 24–72 hours later
- Metadata mismatches (title doesn't match, wrong category) are flagged during ingestion, which can take a few hours
If your rejection arrived quickly, it's technical. If it arrived after more than a day, it's a content or metadata issue that requires a different kind of fix.
The Pre-Upload Checklist
Run through this before every upload:
- Validate the EPUB. Upload to the EPUB Validator and fix every error — not just the first one. Platforms run the same checks.
- Check the TOC. Open your EPUB on an actual device (or Kindle Previewer) and navigate the table of contents. If you can't jump to chapters, neither can your readers.
- Verify the cover. Use the Cover Checker to confirm size, format, and file size against every platform's requirements.
- Check your metadata. Title, author, and language in the OPF must exactly match what you enter in the platform's dashboard.
- Search CSS for external imports. If you're submitting to Apple Books, open every CSS file and search for
@import url(. Remove or replace with embedded fonts. - Fix Word artifacts before converting. Double spaces, tab indents, and misencoded quotes become EPUB errors during conversion. Fix them in the source document first.
Not sure which file format to submit to each platform? See the EPUB vs PDF vs MOBI format guide — it covers which format each major platform accepts and why KDP accepts files that Apple Books rejects.
After a Rejection: What to Do
If you get a rejection, don't re-upload immediately. A second upload with the same problem just adds a new failure to your review history, which can slow future processing.
Do this instead:
- Note the exact error message and when it arrived (minutes vs. hours)
- Upload to the EPUB Validator and save the full report
- Fix every error in the report — not just the one that caused the rejection
- Re-validate to confirm zero errors
- Re-upload once
One clean upload beats five consecutive failed attempts every time.
Get the Complete Guide
"Why Your Book Got Rejected" — the full 2026 EPUB & KDP formatting guide. Every rejection cause, every fix, one place.