The listed settings all look correct. What MIDI to TRS cable are you using? Do you have the link to the product? It has got to be a Type A MIDI Din 5 to TRS cable.
Here’s the cable used to connect the MC6 to the Polymoon:
It was my understanding that a TRS/Stereo 1/4" cable could be used to carry MIDI messages via one of the two expression ports on the MC6 as of firmware 3.9.1, which my unit has been updated to. Is this incorrect? Do I need to connect the Polymoon to the 5-pin out on the MC6?