Your application's REST API has been sporadically returning an error, which clients report as 'Service Unavailable'. You are tasked with identifying the root cause. As part of your troubleshooting process, which HTTP error code are you MOST likely investigating, and what could be its probable reason?
The 500 error code suggests there is an Internal Server Error and might indicate that there is a problem with the server's code or configuration that needs to be addressed.
The 502 error code means Bad Gateway and might be indicative of an error response from an intermediate proxy server that couldn’t receive a good response from the origin server.
The 504 error code represents Gateway Timeout and generally means that a proxy server did not receive a timely response from the upstream server or application.
The 503 error code indicates that the service is temporarily unavailable, likely due to server overload or maintenance.