Please ensure that the valve located in the base of the bottle is not sealed shut. At the top of the dome-shape valve, there is a 12mm slit that can sometimes stick together after washing. Gently squeeze the dome and the slit should pop apart. In order for the platform to move freely up the tube it requires air-flow through the base and up through the tube. Please also check that the inlet hole in the base is not obstructed (i.e. name stickers)
