Hi,
I have search the forum and I could find nothing similar, but like most problems find it is hard to believe I am the first, so feel free to point me in the correct direction.

On my linux box I can plug in my Teensy and my Akai MPK Keyboard into USB, then using aconnect I can patch my MPK Midi Out to the Teensy Midi In, then when playing keys and controls I see the midi messages in Serial Monitor.
My linux box is old and my Mac Laptop is much nicer except I cannot seem patch the two together.

Testing done thus far -
Uploaded new sketches to the teensy from the Mac and audio output works fine and message show up in the serial monitor.
Ran Garageband and can play the instruments via the MPK.

I have been attempting to connect the Midi In & Out using "Audio MIDI Setup" on the mac and they appear to connect but yet nothing.

Mac is at MacOS Catalina - 10.15.3, Arduino 1.8.12 , Teensyduino 1.51

Thanks G