Denre

Thank you for your reply.

As you can read in my previous post:

SiteGround Optimizer 7.2.8
PHP 8.1.3
FPM served by Apache
nginx proxy

The issue is that the apache_response_headers() (a PHP function) does not exist on my system and disabling themes or other plugins won’t solve that.

It would be better if you checked if the function exists

if (function_exists(‘apache_response_headers’)) {
//loop here
}

This latest version did not resolve the issue for me.
I still get the error “Call to undefined function apache_response_headers”.

SiteGround Optimizer 7.2.8
PHP 8.1.3
FPM served by Apache
nginx proxy

For now I commented out the loop on lines 225 to 235 of the File_Cacher_Trait.php