or 503--service unavailable from rfc 2068 hypertext transfer protocol -- http/1.1: 10.5.4 503 service unavailable the server is currently unable to handle the request due to a temporary overloading or maintenance of the server. the implication is that this is a temporary condition which will be alleviated after some delay. if known, the length of the delay may be indicated in a retry-after header. if no retry-after is given, the client should handle the response as it would for a 500 response.note: