Please help: can not connect with Arduino serial port

Hi, I am working on my master project and using Max for the first time.

I would like to use a touch sensor to control the play and stop of a music file on my laptop, so I connect the sensor to the Arduino board and want to use Max for playing the music. However, my Max console can find my serial port connected but cannot print any information sent from Arduino. I don't know why, please help!

Here is my Max code:

by clicking on the toggles, I can manually control the play and stop of the music, but I cannot use sensor to control it.

Here is my Arduino code:

#define TOUCH_SENSOR_PIN 2 // Change to the pin you have the touch sensor connected to

void setup() {
  Serial.begin(9600); // Start serial communication at 9600 baud rate
  pinMode(TOUCH_SENSOR_PIN, INPUT);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  int touchState = digitalRead(TOUCH_SENSOR_PIN); // Read the touch sensor state

  // If the sensor is touched, send a signal
  if (touchState == HIGH) {
    Serial.println("play"); // Send play command
    digitalWrite(LED_BUILTIN, HIGH);
    delay(500); // Debounce delay
  }
  if (touchState == LOW) {
    Serial.println("stop"); // Send play command
    digitalWrite(LED_BUILTIN, LOW);
    delay(500); // Debounce delay
  }
  delay(10); // Short delay to prevent overwhelming the serial port
}

When I clicked the print message on the first line, here is the console:

Thank you guys so much!!!!!