If you get a Page not found Error or There has been a critical error on this website when you try to edit a page with Elementor,

You need to enable the Switch Editor Loader Method from Elementor settings.

The causes of the error can be:

1. ModSecurity or Firewall blocks Elementor’s AJAX request

Many shared or secured hosting platforms use ModSecurity rules that falsely flag Elementor’s editor load request as “suspicious” and block it.
When that request is blocked → Elementor cannot load → WordPress returns a 404 or critical error.

2. Server has issues with the default “Editor loader” method

Some server environments (usually NGINX, LiteSpeed, or custom setups) have incompatibilities with:

• URL rewriting

• REST API endpoint access

• Long URLs or query strings

• Backend iFrame loading

Any of these can break Elementor’s editor load process.

3. Conflicts with caching / security plugins

Plugins like:

• Wordfence

• Sucuri

• iThemes Security

• LiteSpeed Cache
  … can block or rewrite editor requests.

When Elementor can’t load via its standard method, it triggers errors like:

• “Preview could not be loaded”

• “Page Not Found”

• General WP error”

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✅ What “Switch Editor Loader Method” actually does

This setting forces Elementor to use a fallback, more compatible loading path, changing:

• how it loads the editor iframe,

• how it calls AJAX requests, and

• how it passes query variables.

It avoids methods that get blocked by firewalls, caching systems, or restrictive hosting.

So when you enable the switch, Elementor bypasses whatever the host or plugin was blocking — and the editor loads correctly.

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⚠️ Should you keep it enabled?

Yes — if enabling it fixes the problem, leave it ON.
It doesn’t affect visitors or performance; it only changes how Elementor loads the backend editor.