Fatal error: Uncaught RuntimeException: Extension DOM is required. in /home/haowei/pimcore/vendor/symfony/symfony/src/Symfony/Component/Config/Util/XmlUtils.php:45 Stack trace: #0 /home/haowei/pimcore/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php(368): Symfony\Component\Config\Util\XmlUtils::loadFile('/home/haowei/pi...', Array) #1 /home/haowei/pimcore/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php(41): Symfony\Component\DependencyInjection\Loader\XmlFileLoader->parseFileToDOM('/home/haowei/pi...') #2 /home/haowei/pimcore/vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php(97): Symfony\Component\DependencyInjection\Loader\XmlFileLoader->load('web.xml') #3 /home/haowei/pimcore/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Compiler/MergeExtensionConfigurationPass.php(66): Symfony\Bundle\FrameworkBundle\DependencyInjection\FrameworkExtension->load(Array, Object(Symfony\Com in /home/haowei/pimcore/vendor/symfony/symfony/src/Symfony/Component/Config/Util/XmlUtils.php on line 45