Midi Harmonize on VL3 Extreme


Hello, here is my question (sorry if it was already discussed but i haven't found it yet).

If i'm not wrong i can send a midi track from computer to VL3 so that when i sing or play saxophone i get my melody harmonized following the midi changes. Well, so i connect the macbook to VL3 (tested both with a midi/usb cable and with the usb cable supplied with VL3), set ableton live to send midi signal to VL3 and VL3 to receive from midi or usb, depending on the used cable. Then i record some chords in ableton live (at a slow rate, let's say one chord over 2 or 4 bars) and play them. At this point i assume that all settings are ok because i see a "MIDI" writing flashing on bottom of VL3 monitor but... any note i sing or play in the microphone is harmonized in C major or sometimes in G...

Which can be my mistake in this? Thank you for any help!!