Magento 503: Service Temporarily Unavailable
Sometimes Magento shows service temporarily unavailable error after some upgrade or plugin installation etc. You see this warning because the store went to maintenance mode by creating maintenance.flag file in the sites root folder.
The solution is to delete the maintenance.flag file from the root folder and it’s all done. Your store will start working fine.
[root@server /home/username/public_html] rm -f maintenance.flag