Blank Screen and ERR_CONNECTION_CLOSED on WordPress Astra Theme Customizer

Hello,

I am experiencing a blank screen and ERR_CONNECTION_CLOSED errors (status 200 OK) specifically when trying to use the WordPress Astra Theme Customizer. These errors appear in the browser console for admin-ajax.php and various Astra JS files.

I have already attempted the following without success:

• Increased PHP Memory Limit to 512M and max_execution_time to 300.
  
• Added SubstituteMaxLineLength 20M to .htaccess as suggested by Astra documentation (https://wpastra.com/docs/blank-screen/).
  
• Set define( 'CONCATENATE_SCRIPTS', false ); in wp-config.php.
  
• Disabled all other plugins.
  
• Attempted to force-disable Astra’s modern React controls via filters.

Could you please check if there is a ModSecurity rule, Proxy buffer limit or any other thing on my account that is terminating these connections?

Thank you!

Hello,

I'm trying to reproduce the issue. Could you please confirm that the problem occurs on this page?
https://i.imgur.com/vI9ssevm.png

Did the error appear on this page, simply by refreshing it?

Many thanks,

Bye!

Not exactly. The problem is on the Astra theme's Customizer page. See below.

https://i.imgur.com/PXjHz2N.png

Note blank middle part (where live blog content is supposed to be), and errors reported by Console.

The error seems to be known to the Astra theme developers and described in their help article "The Blank Screen in the Customizer Area", where they say The most common reasons are:
* Low PHP memory limit
* Low resources allocation on your account by your hosting provider
* Poor performance on your hosting account
* Resource limit exhaustion