Next time this happens, consider checking-out the UA forum as it likely means that the ITN engine (also serving United.com) went down, for today's thread see http://www.flyertalk.com/forum/showt...21#post4532782

If you are a FULL-tier user of the KVS Tool, you can simply switch to a non-ITN access method (e.g. Amadeus/AUA or Galileo) for uninterrupted access during such an ITN outage.