That's very strange. Sounded like the DAC was working for a brief period of time, and then stopped. I guess only Topping would understand what the error message means. By the way, is there a special reason that you hooked up the DC cable to an Apple USB adapter instead of directly to a USB outlet on your PC?
We'll see what Topping says. Maybe they can help trouble shoot. These things happen but it has soured me on buying from a company with support in China. I'm not going to send it to them. Not worth the cost or time. Hopeful MD refunds me and I'll buy an American made product. I was hesitant to purchase because I read about Toppings QC issue before purchasing.