rwmidi - SysEx message not being sent

Grumpy_Mike

I am using rwmidi in Processing 3.3.5 on a Mac 10.13.3. I can send a note on message and see it on the MIDI monitor and it returns a 1. However, when sending the SysEx message, while it still returns a 1, no message shows up in the MIDI monitor nor the device I am trying to communicate with ( An Arduino Micro ), this is the function I send on a mouse press:-

void mousePressed() {
  println(mouseX,mouseY);
  int ret = output.sendNoteOn(0, 3, 3);
  println("returned from send note", ret);
  ret = output.sendSysex(new byte[] {(byte)0xF0, 1, 2, 3, 4, (byte)0xF7});
  println("returned from sysEx ", ret);
}

Anyone know what I am doing wrong?