Can't get sound to come out audio out jacks

[Bill Smith]

I have an Alesis QuadraSynth Plus Piano keyboard connected with Cakewalk Pro Audio 8 sequencer and Midiman MIDI interface and with the keyboard's audio outs to a mixer. All was fine, but recently a new problem has developed.

Program mode works fine. But when I am in multi mode and on bank Pre4, program 0 (General MIDI) trying to use the sequencer to play back a song, no sound comes out the audio out jacks to the mixer even though both the MIDI in and MIDI out lights are flashing both when I used the sequencer for playback and also when I manually press keys on the keyboard. No sound goes to the mixer.

What setting have I inadvertently changed to cause this problem? I tried doing a soft reset of the keyboard and that did not help. And apparently this keyboard has no hard reset function.