The tracks on my iPhone all became inaudible, as if a global mute had been activated. They play, but I can’t hear them. All the other music apps ARE audible and the Staxx volume is at max. Yet nothing. This muting all happened after a five or ten minute interval. One song all was well; a little later, silence. And at the worst possible time—just hours before a gig. Utterly infuriating and baffling. Please advise. JB