I'm experitmenting with the Twitter API (OAuth). I have a test bed that can tweet from my dev box, but fails in production. I get a status code of 424 returned when trying to tweet.
I can't spot the difference between my live environment and my dev environment so really need to understand what a '424' is, but can find no documentation relating to it.
Wikipedia describes HTTP Response Code 424 as being a Failed Dependency. It's introduced by the WebDAV extensions to HTTP (see the WebDAV RFC). It means that the request you made failed as a result of a previous request failing.
As a high level example (although the actual response codes might be different), you might issue a request to get an OAuth ticket or token for your identity. If this fails and you then make a request using that token, then a 424 might be thrown.
Turned out to be a quirk of classic ASP.
FAILS: Set objXMLHTTP = Server.CreateObject("Msxml2.ServerXMLHTTP.6.0")
WORKS: Set objXMLHTTP = Server.CreateObject("Msxml2.ServerXMLHTTP")