I have a neff induction hob. When I went to use it today when I pressed the on button I got a square light which came on and went off again shortly after. If I tried to press any of the other buttons I got the same square light and could not use the hob. I went through the instruction book but could find nothing with this square symbol. It is still under guarantee - just but wondered if this was something simple and "pilot error". Can anyone help thanks?