Sleep-Modus with mkr fox1200

[herby007]

I try to use the sleep mode with mkf fox1200, but it did not work:

#include <ArduinoLowPower.h>

void setup()
{
  Serial.begin(9600);
  delay(2000);
}

void loop() 
{
  unsigned char i;

  for (i=0; i<=25; i++)
  {
    Serial.println(i);
    delay(250);
  }

  Serial.println("\n\nStart sleep ...\n\n");

  LowPower.sleep(1000);  / Sleep mode for one second

  Serial.println("\n\nEnde sleep ...\n\n");

  for (i=200; i<=225; i++)
  {
    Serial.println(i);
    delay(250);
  }

  delay(1000);

}

The board enters the sleep mode for the first time and never come back.
Where is the problem ?

Thank you for the help.

Herby