# EPUBCheck RSC-006: Remote resource reference is not…

Source: https://epublab.com/epubcheck/rsc-006/ (updated 2026-11-03)

EPUBCheck RSC-006 is an error message: “Remote resource reference is not allowed in this context; resource "…" must be located in the EPUB container.” A resource is loaded from the web in a place where EPUB requires it to be inside the EPUB file.

- Official message (EPUBCheck 5.4.0): Remote resource reference is not allowed in this context; resource "%1$s" must be located in the EPUB container.
- Default severity: Error

## Typical causes

- Images or stylesheets referenced by an http or https URL instead of a file in the book.

## How to fix it

- Download the resource, add it to the EPUB and the manifest, and reference it by a relative path.
- EPUB 3 allows remote audio, video and fonts; those need the remote-resources property on the manifest item of the document that uses them.

Message text and severity: EPUBCheck (W3C, BSD-3-Clause). Explanation: EPUBLab.