Aqualisa Quartz Electric 9.5 turns on after multiple presses

I have a grey Aqualisa Quartz Electric 9.5 shower. Since the last week, if I want to start it, I had to press the start button 30-40 times in order to see the water coming out continuously with pressure. With each press to its start button, very little water comes out and stops. As I continue to press the button, pressure of water gets more. And then maybe after the 40th-50th start button press, the water starts to come continuously with normal pressure. What might be the problem?