At 4:25 of the first period in the Flames/Senators game, Ottawa requested a Coach's Challenge to review whether Sean Monahan interfered with Senators goaltender Mike Condon prior to Sam Bennett's goal.

After reviewing all available replays and consulting with NHL Hockey Operations staff, the Referee confirmed no goaltender interference infractions occurred.
Therefore the original call stands - good goal Calgary Flames.
Since the Coach's Challenge did not result in the original call being overturned, the Ottawa Senators forfeit their time-out.