Fatal error: Uncaught Doctrine\Common\Proxy\Exception\UnexpectedValueException: Your proxy directory "/var/www/html/chamilo/app/cache/" must be writable in /var/www/html/chamilo/vendor/doctrine/common/lib/Doctrine/Common/Proxy/Exception/UnexpectedValueException.php:40 Stack trace: #0 /var/www/html/chamilo/vendor/doctrine/common/lib/Doctrine/Common/Proxy/ProxyGenerator.php(299): Doctrine\Common\Proxy\Exception\UnexpectedValueException::proxyDirectoryNotWritable('/var/www/html/c...') #1 /var/www/html/chamilo/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php(220): Doctrine\Common\Proxy\ProxyGenerator->generateProxyClass(Object(Doctrine\ORM\Mapping\ClassMetadata), '/var/www/html/c...') #2 /var/www/html/chamilo/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php(119): Doctrine\Common\Proxy\AbstractProxyFactory->getProxyDefinition('Chamilo\\CoreBun...') #3 /var/www/html/chamilo/vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php(2682): Doctrine\Common\Proxy\AbstractProxyFactory->get in /var/www/html/chamilo/vendor/doctrine/common/lib/Doctrine/Common/Proxy/Exception/UnexpectedValueException.php on line 40