3.1.5.3 Receiving a HTTP Error or Dropped Connection
When the KKDCP client receives an HTTP error or dropped connection:
On HTTP 403 errors, the client SHOULD set Error (section 3.1.1) to STATUS_AUTHENTICATION_FIREWALL_FAILED.
Otherwise, the client SHOULD set Error (section 3.1.1) to STATUS_NO_LOGON_SERVERS.