btostar

Thank you for the detailed reply and the resources.

I wanted to follow up and share additional info based on further testing. I’ve gone through every troubleshooting step mentioned in the articles you linked. Unfortunately, none of these have resolved the issue.

However, there’s been a new development:

The error appears intermittently, and it seems to be triggered specifically when we paste content into the WordPress editor.

At first, we suspected Google Docs formatting might be causing conflicts (H1/H2 styling, hidden formatting, etc.). To rule this out, we tried:

• converting the Google Docs content into plain text,
• convert that plain text into clean WordPress block HTML,
• and pasting that into the editor.

This workaround briefly helped—we successfully published a few posts. But afterward, the same “invalid JSON response” error returned, even when pasting completely plain text or clean block code.

Notably, when we write directly inside the WordPress editor (without pasting anything), publishing works normally without any errors.

So at the moment:

• Existing draft posts written earlier publish without issues
• New posts fail when any content (even plain text) is pasted into the editor
• But new posts succeed if we manually type inside the editor and don’t paste anything

Given this pattern, I’m not sure if this is pointing toward a REST API issue, a server-level rule interfering with POST requests, something related to sanitization or content filters, or an editor-specific conflict.

If anyone has run into JSON response errors tied to pasted content/editor behavior, or if there are additional areas we should inspect, any guidance would be very helpful.

Thank you again for your support!