3.6.5.2.1.3 Processing Details
Upon successful authentication the server MUST return the Store Entry (section 2.2.2.9) represented by the object in [Server State].ProxyStore that has a key value with the same string value as {Key}.
If after successful authentication a Store Entry with the same string value as {Key} is not present in [Server State].ProxyStore, the server MUST return an HTTP error code of 404.