DDJ-FLX4 Headphones

I use the DDJ-FLX4 with Bluetooth via my smartphone and i wanna know, if I can use my headphones like this. If I plug them into the controller I get no answer in the headphones. Do I have to activate a special function in the App or something like this? Or can't I use my headphones in this situation?

I also wanna know if there is a reason why the light effects of the controller don't work like normal, when I connect it to my smartphone.

Thx for your help!!