Fatal error: Uncaught Symfony\Component\Filesystem\Exception\IOException: Unable to write to the "/var/www/demo.apollotheme.com/demomodule17x/var/cache/dev/yaml" directory. in /var/www/demo.apollotheme.com/demo/lib_common/1.7.6.5/vendor/symfony/symfony/src/Symfony/Component/Filesystem/Filesystem.php:681 Stack trace: #0 /var/www/demo.apollotheme.com/demo/lib_common/1.7.6.5/vendor/symfony/symfony/src/Symfony/Component/Config/ResourceCheckerConfigCache.php(124): Symfony\Component\Filesystem\Filesystem->dumpFile('/var/www/demo.a...', '<?php return ar...') #1 /var/www/demo.apollotheme.com/demomodule17x/src/Core/Util/File/YamlParser.php(92): Symfony\Component\Config\ResourceCheckerConfigCache->write('<?php return ar...', Array) #2 /var/www/demo.apollotheme.com/demomodule17x/src/Adapter/Container/DoctrineBuilderExtension.php(61): PrestaShop\PrestaShop\Core\Util\File\YamlParser->parse('/var/www/demo.a...') #3 /var/www/demo.apollotheme.com/demomodule17x/src/Adapter/ContainerBuilder.php(169): PrestaShop\PrestaShop\Adapter\Container in /var/www/demo.apollotheme.com/demo/lib_common/1.7.6.5/vendor/symfony/symfony/src/Symfony/Component/Filesystem/Filesystem.php on line 681