title: What does CFNetwork error -4 in domain CFStreamErrorHTTP mean?
body: <p>A customer is reporting a connection failure with a strange profile: it apparently only fails for the very first URL request via CFNetwork since the app has launched.</p>
  
  <p>The error code apparently being returned by CFNetwork is domain CFStreamErrorHTTP, but with error code -4, which does not correspond to any publicly defined error code for this domain.</p>
  
  <p>In CFHTTPStream.h, the publicly defined error codes for CFStreamErrorHTTP end auspiciously at -3, strongly hinting that -4 may be an error code that Apple is using but which has not yet been publicly documented.</p>
  
  <p>Any idea what's going on here? Has anybody else seen this error code and found rhyme or reason for it?</p>