Nano33 iot running sketch with rtczero stops after a while

[vapol]

Hello!
I am a new user in adruino world and I run the following sketch trying to use the internal rtc of nano33 iot. After some times of displaying the date and time in the serial monitor it stops displaying. Have someone faced the same problem? Please advice me what to do. Thanks a lot for your time.

#include <RTCZero.h>

/* Create an rtc object */

RTCZero rtc;

/* Change these values to set the current initial time */

const byte seconds = 0;

const byte minutes = 0;

const byte hours = 16;

/* Change these values to set the current initial date */

const byte day = 15;

const byte month = 6;

const byte year = 15;

void setup()
{

  Serial.begin(115200);

  rtc.begin(); // initialize RTC

  // Set the time

  rtc.setHours(hours);

  rtc.setMinutes(minutes);

  rtc.setSeconds(seconds);

  // Set the date

  rtc.setDay(day);

  rtc.setMonth(month);

  rtc.setYear(year);

  // you can use also

  //rtc.setTime(hours, minutes, seconds);

  //rtc.setDate(day, month, year);
}

void loop()
{

  // Print date...

  print2digits(rtc.getDay());

  Serial.print("/");

  print2digits(rtc.getMonth());

  Serial.print("/");

  print2digits(rtc.getYear());

  Serial.print(" ");

  // ...and time

  print2digits(rtc.getHours());

  Serial.print(":");

  print2digits(rtc.getMinutes());

  Serial.print(":");

  print2digits(rtc.getSeconds());

  Serial.println();

  delay(1000);
}

void print2digits(int number) {

  if (number < 10) {

    Serial.print("0"); // print a 0 before if the number is < than 10

  }

  Serial.print(number);
}