PHP errors during an Ajax request\WP_MEMORY_LIMIT

Hello,

after updating to the latest wp version my website is not responding and I got a “critical error” in php code. The plugin “Query Monitor” shows that the error is in the wp_config.php and it says “Constant WP_MEMORY_LIMIT already defined”. In the code I see “wp-config.php:96
define()
wp-config.php:96”
any ideas?
The website is running on the Astra theme + elementor. It is organised like so: astra theme-> astra child theme actevated->elementor pro plugin for website building.
When I swotch to “hestia theme” or “neve” theme the website works, but I don’t really want to adjust it from scratch again to one of these themes, it’s a lot of work.
Any ideas how to fix this bug?

The page I need help with: [log in to see the link]