Hello I've only had my Stadler Form Oskar big for a week, but now it won't start. The tank emptied overnight, the fan stopped and the red LED indicator started to light up. I then refilled the tank, the red LED light switched off and the blue LED lights started to light up again. But nothing else happened. Even after switching it off and on again several times, nothing happens. Is the humidifier faulty or am I doing something wrong? Normally, it automatically switched on again immediately after filling.