Did you select a narrow-band filter in NaP3? that would kill almost all Ft8 audio, and it's easy do accidentally do by hitting a button on the main screen.? Hitting the mute button in the bottom left would also do it.
Do you still see the characteristic spectral display in NaP3? Or is it idle?? If it is there, you have the signal from the QMX+, and audio out of NaP3 is a matter of getting software and computer settings fixed again.
Is your antenna still connected? (cables and wires break sometimes, or connectors need reseated).? This has happened to me.
Does NaP3 (and WSJT-x) still see the radio frequency and change it?? If so, the USB cable and data connection are fine.? And if those two are fine, the QMX+ is fine, because all of the logic to get I/Q out the USB is in firmware - so if there was a glitch, it would come back after a restart.? So the problem is likely somewhere in the software connections inside your computer.
