Nano BLE Bootloader Crash?

Projects Programming
15 
  int sensorOutValue = 0;       //value from outside pressure sensor
  
void setup() {
  
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);

  // initialize analog pin A0 as sensor input
  pinMode(A0, INPUT_PULLUP);

  // setup serial communication
  Serial.begin(9600);
}


void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second

  // read the analog in values from digital pin:
  sensorOutValue = analogRead(A0);

  Serial.println("sensor values = " );
  Serial.println(sensorOutValue);    
}