Cache unable to write to /cache/.

Hello,
I just set up a new instance of CodeIgniter. Unfortunately I get the following error "Cache unable to write to /cache/.". For some reason, CodeIgniter has a need to cache write to /cache among other system folders, not in web folder. If I create a folder, I get an error that mkdir cannot be executed. CodeIgniter is running under www-data:www-data.
For some reason constant WRITEPATH is "/".

PHP - 8.1.8

Do you have any idea how fix?
Thank you