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Common EPUB upload errors and how to fix them

Most EPUB upload errors are easy fixes: invalid markup, missing navigation, bad cover references, or remote resources. Here's how to clear the common ones.

Help centerTroubleshootingCommon EPUB upload errors and how to fix them

Last updated June 15, 2026

Most EPUB errors come from a handful of common causes — and Chiify auto-fixes many of them for you. Here is what the frequent ones mean and how to clear them.

Chiify fixes a lot automatically

On upload, Chiify runs EPUBCheck, auto-heals common structural problems, and upgrades EPUB 2 to EPUB 3 during delivery. So some issues never reach you. When one does, here is the playbook.

Frequent errors

  • Missing navigation / table of contents. Your EPUB needs a clickable nav. The simplest fix is to upload your DOCX and let Chiify build a clean EPUB with proper navigation — see clickable table of contents.
  • Embedded cover not found or not an image. The cover inside the file is broken; re-upload and let Chiify inject the cover. See cover upload errors.
  • Remote resources / external links to fonts or styles. EPUBs must be self-contained. Chiify strips offending remote references during healing; if it persists, rebuild from DOCX.
  • Invalid markup (bad attribute, invalid id, src not a URI). These come from messy export tools. The reliable fix is to re-upload the DOCX for a fresh, valid conversion.
  • Placeholder text detected. Not a format error — remove template/boilerplate text. See why was my book blocked.

The one fix that solves most cases

When in doubt, upload your Word DOCX instead of a hand-made EPUB. Chiify's free conversion produces a valid EPUB 3 that passes validation cleanly.

Still need help? Open a ticket from your dashboard or email [email protected] — a real person replies.

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