Restrict Polyphony

I have a miditrack in Elements which should send polyphonic notes to my drumcomputer (Yamaha RY 10). But it plays only one note at a time. When I open MIDI-Functions-Restrict Polyphony, I can change ‘1 voices’ to ‘8 voices’. But when i click ok, there’s still no polyphony and when I open Restrict Polyphony again, it says ‘1 voices’ again. Why doesn’t this work and how can I get polyphony?