How to Fix “Updating Failed” in Gutenberg

It should be fully clear what the issue is if you look on the screenshot below:

On this screenshot you can also see that I am using custom background and custom fonts. If you’re interested in how to do that, check this tutorial.

Coming back to our issue, it happened just after I moved my website to localhost.

Here is a couple error messages you can find in the browser console:

• “Uncaught (in promise): The response is not a valid JSON response.”
• “Uncaught (in promise): Not found”
• “Failed to load resource: the server responded with a status of 404 (Not Found)”

I think many of you already know how to fix this issue 😁 Have some ideas?

If not, my next question is – do you use permalinks (pretty URLs) on your website? 🤔

Yes, yes, all you have to do is to go to Settings > Permalinks from WordPress admin menu and hit the button “Save changes” without changing anything. That’s all!

Related post

• Why Inserter Dialog is not Available in Gutenberg and You Can’t Add Blocks

Misha Rudrastyh

I develop websites since 2008, so it is total of 13 years of experience, oh my gosh. Most of all I love love love to create websites with WordPress and Gutenberg, some ideas and thoughts I share throughout my blog.

Need some developer help? Contact me