I've had my Zgemma knock out my home network, flooding the network with weird packets! The Zgemma itself would be in a hung state. I never did get to the bottom of the network flooding but discovered if I changed network switch to another make/model, it was able to restrict the impact on the network. The Zgemma still hangs to this day, but it no longer floods the networ. It may be the same, try unplugging the Zgemma from the network and see if that stops the Q box from freezing?