MIDI device won't activate despite actually existing

I’m sending a note on/off loop from Ableton on a Mac to my PC and on the PC, MIDIOX sees the trigger over and over again as expected.

However, Onyx won’t allow me to activate that port. I click activate and it deactivates itself. Why would Onyx not allow me to turn on the detected port?

Also, if I scan MIDI connection, any active connection is toggled to inactive. If I scan again, they’re turned back on. Counterintuitive? Doesn’t make sense.

Okay, weird. Apparently if MIDIOX is open prior to opening ONYX, it prevents ONYX from taking the port. Grrr…is this a Windows thing?

Seems it’s working now.