ds3132 no display but upload ok

hi i’m having this ds3231 and lcd 16x2 with I2C, SDA to SDA, CLR to CLR connection. RTC already properly set. Upload has no errors but also no display. As per actual label on the lcd module, RS is 4th pin from the left side. Even if I change the pin number to LiquidCrystal lcd(0, 2, 4, 5, 6, 7), still no display.
Pls. help to troubleshoot the code. thanks.

/*
* Arduino DS3231 Real Time Clock Module Tutorial
*
* Crated by Dejan Nedelkovski,
* www.HowToMechatronics.com
*
* DS3231 Library made by Henning Karlsen which can be found and downloaded from his website, www.rinkydinkelectronics.com.
*
*/
#include <DS3231.h>
#include <LiquidCrystal.h> // includes the LiquidCrystal Library 
#include <LiquidCrystal_I2C.h>
#include <Wire.h>


DS3231  rtc(SDA, SCL);
LiquidCrystal lcd(4, 6, 11, 12, 13, 14); // Creates an LC object. Parameters: (rs, enable, d4, d5, d6, d7) 
void setup() { 
 rtc.begin(); // Initialize the rtc object
 lcd.begin(16,2); // Initializes the interface to the LCD screen, and specifies the dimensions (width and height) of the display } 
}
void loop() { 
 lcd.setCursor(0,0);
 lcd.print("Time:  ");
 lcd.print(rtc.getTimeStr());
 
 lcd.setCursor(0,1);
 lcd.print("Date: ");
 lcd.print(rtc.getDateStr());
 
 delay(1000); 
}

Where is the problem happening? Add Serial.begin() and Serial.println() statements to find out.

Why are you including the LiquidCrystal_I2C header file when you don't have an I2C LCD?