The solutions is use:
MIDI.begin();
Serial.begin(115200);
and NOT:
MIDI.begin(MIDI_CHANNEL_OMNI);
on the setup.
Following the tip in the documentation: The Hairless MIDI<->Serial Bridge
I hope tu be useful 
Marc
The solutions is use:
MIDI.begin();
Serial.begin(115200);
and NOT:
MIDI.begin(MIDI_CHANNEL_OMNI);
on the setup.
Following the tip in the documentation: The Hairless MIDI<->Serial Bridge
I hope tu be useful
Marc