Hello.
It’s weird, but the bug was in Google Chrome.
This error occurred suddenly and only on my website. Before everything worked.
After reinstalling Chrome, everything is fine.
I’ve solved this problem.
I found a solution somewhere on google.
I’ve added to the wp-config.php the following lines:
define( 'WP_MEMORY_LIMIT', '512M' );
define( 'WP_MAX_MEMORY_LIMIT', '1024M' );
