There is a switch that allows you to use USB midi OR Midi Cable Midi it is “Press DATA 3 and DATA 2 at the same time
You will see a Midi PLug ICON on the Display”
If you see this icon, you are sending midi over usb ONLY.
They call this function “MIDI out from USB”
If you “Press DATA 3 and DATA 2 at the same time again, the Midi Plug icon on the display disappears.