title: Facebook iOS SDK returns error "com.facebook.sdk error 4"
body: <p>Today we started to get the following error when using the Facebook SDK for iOS to try and query some pages streams:</p>
  
  <p>Error Domain=com.facebook.sdk Code=4 "The operation couldn’t be completed. (com.facebook.sdk error 4.)" UserInfo=0xb8606d0 {com.facebook.sdk:HTTPStatusCode=400, com.facebook.sdk:ErrorSessionKey=
  
  <p>This code used to work for months. Anyone knows what error code 4 means???</p>