Hello!

I'm new around here, just trying to figure out what I thought was going to be a quick project.

I'm attempting to use a Teensy 4.0 to build out a MIDI interface. Running into some issues with this though. I have two Teensy 4.0s and it seems I cannot receive any messages from any of my USB enabled MIDI devices while using a T4 attached via USB to my MBP running the latest macOS. I tried routing in the Audio MIDI Setup but was unable to route my sequencer or keyboard to my Teensy in a way that would result in any messages being printed via InputRead, the basic script. I am using Serial + MIDI mode in tools. I'm running a basic script but I've attached the code here. It receives no errors when compiling or running to my knowledge. Please tell me if I'm missing any info that may track down the issue.

Edit: upon reread to be more clear: I was using one T4 at a time but neither were working. I'm convinced I have something in my setup wrong but I can't figure out what.

Code:
/* Receive Incoming USB MIDI by reading data.  This approach
   gives you access to incoming MIDI message data, but requires
   more work to use that data.  For the simpler function-based
   approach, see InputFunctionsBasic and InputFunctionsComplete.

   Use the Arduino Serial Monitor to view the messages
   as Teensy receives them by USB MIDI

   You must select MIDI from the "Tools > USB Type" menu

   This example code is in the public domain.
*/

void setup() {
  Serial.begin(115200);
}

void loop() {
  // usbMIDI.read() needs to be called rapidly from loop().  When
  // each MIDI messages arrives, it return true.  The message must
  // be fully processed before usbMIDI.read() is called again.
  if (usbMIDI.read()) {
    processMIDI();
  }
}

void processMIDI(void) {
  byte type, channel, data1, data2, cable;

  // fetch the MIDI message, defined by these 5 numbers (except SysEX)
  //
  type = usbMIDI.getType();       // which MIDI message, 128-255
  channel = usbMIDI.getChannel(); // which MIDI channel, 1-16
  data1 = usbMIDI.getData1();     // first data byte of message, 0-127
  data2 = usbMIDI.getData2();     // second data byte of message, 0-127
  cable = usbMIDI.getCable();     // which virtual cable with MIDIx8, 0-7

  // uncomment if using multiple virtual cables
  //Serial.print("cable ");
  //Serial.print(cable, DEC);
  //Serial.print(": ");

  // print info about the message
  //
  switch (type) {
    case usbMIDI.NoteOff: // 0x80
      Serial.print("Note Off, ch=");
      Serial.print(channel, DEC);
      Serial.print(", note=");
      Serial.print(data1, DEC);
      Serial.print(", velocity=");
      Serial.println(data2, DEC);
      break;

    case usbMIDI.NoteOn: // 0x90
      Serial.print("Note On, ch=");
      Serial.print(channel, DEC);
      Serial.print(", note=");
      Serial.print(data1, DEC);
      Serial.print(", velocity=");
      Serial.println(data2, DEC);
      break;

    case usbMIDI.AfterTouchPoly: // 0xA0
      Serial.print("AfterTouch Change, ch=");
      Serial.print(channel, DEC);
      Serial.print(", note=");
      Serial.print(data1, DEC);
      Serial.print(", velocity=");
      Serial.println(data2, DEC);
      break;

    case usbMIDI.ControlChange: // 0xB0
      Serial.print("Control Change, ch=");
      Serial.print(channel, DEC);
      Serial.print(", control=");
      Serial.print(data1, DEC);
      Serial.print(", value=");
      Serial.println(data2, DEC);
      break;

    case usbMIDI.ProgramChange: // 0xC0
      Serial.print("Program Change, ch=");
      Serial.print(channel, DEC);
      Serial.print(", program=");
      Serial.println(data1, DEC);
      break;

    case usbMIDI.AfterTouchChannel: // 0xD0
      Serial.print("After Touch, ch=");
      Serial.print(channel, DEC);
      Serial.print(", pressure=");
      Serial.println(data1, DEC);
      break;

    case usbMIDI.PitchBend: // 0xE0
      Serial.print("Pitch Change, ch=");
      Serial.print(channel, DEC);
      Serial.print(", pitch=");
      Serial.println(data1 + data2 * 128, DEC);
      break;

    case usbMIDI.SystemExclusive: // 0xF0
      // Messages larger than usbMIDI's internal buffer are truncated.
      // To receive large messages, you *must* use the 3-input function
      // handler.  See InputFunctionsComplete for details.
      Serial.print("SysEx Message: ");
      printBytes(usbMIDI.getSysExArray(), data1 + data2 * 256);
      Serial.println();
      break;

    case usbMIDI.TimeCodeQuarterFrame: // 0xF1
      Serial.print("TimeCode, index=");
      Serial.print(data1 >> 4, DEC);
      Serial.print(", digit=");
      Serial.println(data1 & 15, DEC);
      break;

    case usbMIDI.SongPosition: // 0xF2
      Serial.print("Song Position, beat=");
      Serial.println(data1 + data2 * 128);
      break;

    case usbMIDI.SongSelect: // 0xF3
      Serial.print("Sond Select, song=");
      Serial.println(data1, DEC);
      break;

    case usbMIDI.TuneRequest: // 0xF6
      Serial.println("Tune Request");
      break;

    case usbMIDI.Clock: // 0xF8
      Serial.println("Clock");
      break;

    case usbMIDI.Start: // 0xFA
      Serial.println("Start");
      break;

    case usbMIDI.Continue: // 0xFB
      Serial.println("Continue");
      break;

    case usbMIDI.Stop: // 0xFC
      Serial.println("Stop");
      break;

    case usbMIDI.ActiveSensing: // 0xFE
      Serial.println("Actvice Sensing");
      break;

    case usbMIDI.SystemReset: // 0xFF
      Serial.println("System Reset");
      break;

    default:
      Serial.println("Opps, an unknown MIDI message type!");
  }
}


void printBytes(const byte *data, unsigned int size) {
  while (size > 0) {
    byte b = *data++;
    if (b < 16) Serial.print('0');
    Serial.print(b, HEX);
    if (size > 1) Serial.print(' ');
    size = size - 1;
  }
}