The Wall Street Journal and United Airlines were both experiencing problems Wednesday morning. The NYSE halted all trading, citing unexplained technical problems, while United Airlines grounded all flights. The WSJ.com website returned a 504 error indicating there was something seriously wrong with the news organization’s servers. White House, the Department of Homeland Security, and the NYSE issued statements saying the outages were not part of some sort of cyber attack. News organizations citing unnamed sources said the outage was the result of a software update that was installed before trading began.”]