URmkII won’t switch on on ipad or iphone

Today, i plugged my ipad the usual way into the interface and it wont light up. I hear a soft rhythmic knocking on my monitors and that’s all. It showed on my ipad home screen that i need to unlock the ipad to use the device so it somehow detects the interface. But when i unlock the ipad the interface doesn’t switch on. Changed the usb cable just to be sure it’s not the problem. The camera connector is fine. Any advice?