First check if the water is heating. Put it on fast wash cycle & water should heat on first wash. On normal wash the first wash is cold then after drain & refill for 2nd wash it heats. The soap flap does not open until water reaches 30 deg C. If water is heating then there is either a fault with the opening mechanism on the dispenser or a fault with the control board.
Lincoln Appliance NZ, August 2017