magento e-shop

Magento 2 e-shop. Dedicated server. Error on adding product to cart on the product detail page: "We can't add this item to your shopping cart right now"
The error also occurs on clean Magento Luma installation, so it is probably related to the server settings. Exception log:
Clean installation, Magento 2.4.2 Luma
Notice: tempnam(): file created in the system's temporary directory in vendor/magento/zendframework1/library/Zend/Cache/Backend.php on line 203
My magento site same error, but diferent path:
vendor\magento\zendframework1\library\Zend\Cache\Backend\File.php:99
Tried this solution: https://stackoverflow.com/questions/54214726/magento2-cant-add-products-to-cart-we-cant-add-this-item-to-your-shopping-c Asked hosting guys to add to php.ini:
sys_temp_dir="/absolute/path/to/magento2/var/tmp"
session.save_path="/absolute/path/to/magento2/var/tmp"
session.cookie_path="/absolute/path/to/magento2/var/tmp"
Nothing changes. The var/cache permissions are good. Fixed by changing vendor\magento\zendframework1\library\Zend\Cache\Backend\File.php:99 'cache_dir' => null to 'cache_dir' => 'absolute path/var/cache'.
I would like to fix this error without changing core files or creating a new module.