LCD with I2C not displaying characters

nothing it just blinks 1 time and then goes black

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x3F, 16, 2); 

void setup() 
{
 lcd.begin(16,2);
 lcd.backlight();
 lcd.setCursor(0, 0); //DP0 of Top Line
 lcd.print("Hello!");
}


void loop() 
{

}