What is a good troubleshooting method for Magento 503 errors?

  • Answered
Site is getting Magento 503 error, all other web pages on the server work fine. Also indicates:
Service Temporarily Unavailable

The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
This error is typically caused by a planned outage within the Magento configuration, typically from the maintenance flag being enabled. Inside the root directory for your Magento installation, you may see a file named maintenance.flag. Rename that file to something like maintenance.flag.old and it should come back online.