At 16:07 of the third period in the Blackhawks/Blues game, St. Louis requested a Coach's Challenge to review whether a Chicago player interfered with St. Louis goaltender Jake Allen prior to Alex DeBrincat's goal.
After reviewing all available replays and consulting with NHL Hockey Operations staff, the Referee determined that the actions of St. Louis' Kyle Brodziak caused Chicago's Ryan Hartman to contact Allen before the puck crossed the goal line. The decision was made in accordance with Note 2 of Rule 78.7 (ii) which states, in part, "that the goal on the ice should have been allowed because (ii) the attacking Player was pushed, shoved or fouled by a defending Player causing the attacking Player to come into contact with the goalkeeper."
Therefore the original call stands - good goal Chicago Blackhawks.
Since the Coach's Challenge did not result in the original call being overturned, the St. Louis Blues forfeit their time-out.