Using multitrack output feature connected to a presonus 24r studio live iii rack mixer using a latest version iPad connected with an usb C to mixer with no sound. Worked well first time, even multiple times after but moody, next day plug up cable no sound. Seems to be Malfunctioning whenever it chooses… channels on presonus mixer being used set to usb and is ST3 is recognizing the correct I/O in the settings of its output window. What am I missing or doing incorrectly! Anyone.. Many thanks!