Fatal error: Uncaught Zend_Cache_Exception: cache_dir "/var/www/html/demomage11/var/cache/" is not writable in /var/www/html/demomage11/vendor/magento/zend-cache/library/Zend/Cache.php:209
Stack trace:
#0 /var/www/html/demomage11/vendor/magento/zend-cache/library/Zend/Cache/Backend/File.php(180): Zend_Cache::throwException()
#1 /var/www/html/demomage11/vendor/colinmollenhour/cache-backend-file/File.php(86): Zend_Cache_Backend_File->setCacheDir()
#2 /var/www/html/demomage11/vendor/magento/zend-cache/library/Zend/Cache.php(153): Cm_Cache_Backend_File->__construct()
#3 /var/www/html/demomage11/vendor/magento/zend-cache/library/Zend/Cache.php(94): Zend_Cache::_makeBackend()
#4 /var/www/html/demomage11/vendor/magento/framework/App/Cache/Frontend/Factory.php(435): Zend_Cache::factory()
#5 /var/www/html/demomage11/vendor/magento/framework/Cache/Frontend/Adapter/Zend.php(38): Magento\Framework\App\Cache\Frontend\Factory->Magento\Framework\App\Cache\Frontend\{closure}()
#6 /var/www/html/demomage11/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php(121): Magento\Framework\Cache\Frontend\Adapter\Zend->__construct()
#7 /var/www/html/demomage11/vendor/magento/framework/ObjectManager/Factory/Dynamic/Developer.php(66): Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject()
#8 /var/www/html/demomage11/vendor/magento/framework/ObjectManager/ObjectManager.php(56): Magento\Framework\ObjectManager\Factory\Dynamic\Developer->create()
#9 /var/www/html/demomage11/vendor/magento/framework/App/Cache/Frontend/Factory.php(431): Magento\Framework\ObjectManager\ObjectManager->create()
#10 /var/www/html/demomage11/vendor/magento/framework/App/Cache/Frontend/Factory.php(178): Magento\Framework\App\Cache\Frontend\Factory->createCacheWithDefaultOptions()
#11 /var/www/html/demomage11/vendor/magento/framework/App/Cache/Frontend/Pool.php(69): Magento\Framework\App\Cache\Frontend\Factory->create()
#12 /var/www/html/demomage11/vendor/magento/framework/App/Cache/Frontend/Pool.php(156): Magento\Framework\App\Cache\Frontend\Pool->_initialize()
#13 /var/www/html/demomage11/vendor/magento/framework/App/Cache/Type/FrontendPool.php(87): Magento\Framework\App\Cache\Frontend\Pool->get()
#14 /var/www/html/demomage11/vendor/magento/framework/App/Cache/Type/Config.php(52): Magento\Framework\App\Cache\Type\FrontendPool->get()
#15 /var/www/html/demomage11/vendor/magento/framework/Cache/Frontend/Decorator/Bare.php(65): Magento\Framework\App\Cache\Type\Config->_getFrontend()
#16 /var/www/html/demomage11/vendor/magento/framework/App/ObjectManager/ConfigLoader.php(73): Magento\Framework\Cache\Frontend\Decorator\Bare->load()
#17 /var/www/html/demomage11/vendor/magento/framework/App/ObjectManager/Environment/Developer.php(79): Magento\Framework\App\ObjectManager\ConfigLoader->load()
#18 /var/www/html/demomage11/vendor/magento/framework/App/ObjectManagerFactory.php(191): Magento\Framework\App\ObjectManager\Environment\Developer->configureObjectManager()
#19 /var/www/html/demomage11/vendor/magento/framework/App/Bootstrap.php(212): Magento\Framework\App\ObjectManagerFactory->create()
#20 /var/www/html/demomage11/vendor/magento/framework/App/Bootstrap.php(127): Magento\Framework\App\Bootstrap->__construct()
#21 /var/www/html/demomage11/pub/index.php(28): Magento\Framework\App\Bootstrap::create()
#22 {main}
thrown in /var/www/html/demomage11/vendor/magento/zend-cache/library/Zend/Cache.php on line 209