I looked into the Magento system log file (var/log/system.log). There I saw the exact error. The error is as below:- Recoverable Error: Argument 1 passed to Mage_Core_Model_Store::setWebsite() must be an instance of Mage_Core_Model_Website, null given, called in YOUR_PATH\app\code\core\Mage\Core\Model\App.php on line 555 and defined in YOUR_PATH\app\code\core\Mage\Core\Model\Store.php on line 285 Recoverable Error: Argument 1 passed to Mage_Core_Model_Store_Group::setWebsite()… Read more »