keyboard backlighting not working anymore

Hi, I saw several threads regarding this problem but cant fix it. My keyboard backlights are suddenly not working anymore. If I press fn + space nothing happens. Before it showed the symbol on the screen for lights on, off etc. It is also not working in bios. I have read that lots of people fixed it by fixing a cable on the back of the laptop. But as I dont see anything happen on the screen I am not sure, whether its a hardware or software problem for me.

Laptop is a new Lenovo Yoga 7i Aura Edition.

Please help!