/var/www/html/magento/generated/code/Magento/Framework/App/Http/Interceptor.php.12876 file couldn't be written. in magento 2 code example
Example: ReflectionException: Class Magento\Framework\App\Http\Interceptor does not exist in
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:Deploy -f
chmod -R 777 var/ generated/