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Editor & Publishing Guides for WordPress

1 guide covers editor & publishing problems in WordPress, from the first symptom to the fix that holds.

The block editor fails in distinctive ways: a red 'Updating failed' notice, a white editor screen, or a JSON response error that points at the REST API. These guides explain what the editor is actually doing when it saves, why permalinks, security plugins, and SSL mixed content can break that request, and how to get publishing working again without switching editors or losing your content.

Updating Failed: The Response Is Not a Valid JSON Response (WordPress Fix)

You hit Update, the block editor turns red, and WordPress tells you the response is not a valid JSON response. The post is usually fine. What is broken is the REST API request between the editor and your server. Here is the order I work through it, from permalinks to SSL to the mod_security rule your host will not mention.

Aug 8, 2026

Editor & Publishing Guides for WordPress

Updating Failed: The Response Is Not a Valid JSON Response (WordPress Fix)

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