The government contract to carry mail to Utah by the Brigham Young Express and Carrying Company (called the Y. X. Company) was cancelled. Mail service to Utah was thus discontinued, cutting off the normal flow of information which would have alerted Gov. Young that he was to be replaced and, further, that an army was preparing to march to Utah.
[Source: Hale, Van, Mormon Miscellaneous, Utah War Chronology, http://www.mormonmiscellaneous.com/utahwar/id2.html]