LEONARDO - Serial Port not working?

Hello,

I uploaded a sketch:

void setup()
{
Serial.begin(9600);
Serial.println("Starting.....");
}

void loop()
{
Serial.println("In the loop.....");
delay(1000);
}

It didnt work out (Serial Monitor is blank (no output).

I added some code just to check whether the board is working:

int led = 13;
void setup() {
  pinMode(led, OUTPUT);
  Serial.begin(9600);
  Serial.println("Starting.....");
}
void loop() {
  for(int x = 0; x < 300; x = x + 10){
    digitalWrite(led, HIGH);
    delay(x);               
    digitalWrite(led, LOW);
    delay(100);
    Serial.println(x);
  }
}

The led started to blink, but still no output on the Serial Monitor.

I added a line with Serial check (in the setup section):

 while (!Serial) {
   ; // wait for serial port to connect. Needed for Leonardo only
  }

It comes trom IDE examples. I saw this comment “needed for Leonardo only” - and I started to wonder whether the Leonardo board requires some different code to start serial?

After adding this code to setup section - the led did not blink (still nothing on the Serial Monitor)