some common status returned by http/1.1 (taken from this document).

200 OK

The request has succeeded.

301 Moved Permanently

The requested resource has been assigned a new permanent URI and any future references to this resource SHOULD use one of the returned URIs.

304 Not Modified

No new data.

400 Bad Request

The request could not be understood by the server due to malformed syntax.

401 Unauthorized

The request requires user authentication. The response MUST include a WWW-Authenticate header field containing a challenge applicable to the requested resource.

403 Forbidden

The server understood the request, but is refusing to fulfill it.

404 Not Found

The server has not found anything matching the Request-URI.

410 Gone

The requested resource is no longer available at the server and no forwarding address is known.

500 Internal Server Error

The server encountered an unexpected condition which prevented it from fulfilling the request.

502 Bad Gateway

-

503 Service Unavailable

-