A list of common HTTP status codes for production environments

200-OK, the server successfully returned to the Web page
-standard response for successful HTTP requests.

301-moved permanently (permanent jump), the requested page has been permanently redirected to the new location.
-This and all of the future requests should is directed to the given.

403-forbidden (no access), the server rejects the request
-Forbidden request (matches a deny filter) = HTTP 403
-the request was a legal request and the server is refusing to respond to it.

404-not Found, the server could not find the requested page.
-The requested resource could is not being found but may is available again in the future.

500-internal Server error (internal server errors)
-Internal Error in Haproxy = HTTP 500
-A generic error message, given when no more specific message is suitable.

502-bad Gateway (Bad Gateway), typically when the gateway server requests the backend service, the backend service does not return the results correctly as the HTTP protocol.
-the server returned an invalid or incomplete response = HTTP 502
-The server was acting as a gateway or proxy and received a invalid response from the upstream server.

503-service unavailable (service is not currently available), may be due to overloading or downtime maintenance.
-No server is available to handle the request + = 503
-The server is currently unavailable (because it was overloaded or down for maintenance).

504-gateway Timeout (gateway timeout), typically when a gateway server requests a backend service, the backend service does not complete the service in a specific time period.
-The server failed to reply in time + = HTTP 504
-The server was acting as a gateway or proxy and do not receive a timely response from the upstream server.

A list of common HTTP status codes for production environments