oled lcd 128x64 not showing anything

Hi, i am trying to run a simple code on my lcd but after uploading the code nothing is showing on the lcd screen.

it was okay at first.

I have checked with i2c scanner and the address showed up it is 0x3C.

Yes, i did uncomment #define SSD1306_128_64

here is the example code

#include <Wire.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>

// OLED display TWI address
#define OLED_ADDR 0x3C

Adafruit_SSD1306 display(-1);

#if (SSD1306_LCDHEIGHT != 64)
#error(“Height incorrect, please fix Adafruit_SSD1306.h!”);
#endif

void setup() {
// initialize and clear display
display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
display.clearDisplay();
display.display();

// display a pixel in each corner of the screen
display.drawPixel(0, 0, WHITE);
display.drawPixel(127, 0, WHITE);
display.drawPixel(0, 63, WHITE);
display.drawPixel(127, 63, WHITE);

// display a line of text
display.setTextSize(1);
display.setTextColor(WHITE);
display.setCursor(27,30);
display.print(“Hello, world!”);

// update display with all of the above graphics
display.display();
}

void loop() {
// put your main code here, to run repeatedly:

}

I am using nodemcu.

here is the connection

LCD NodeMCU
GND → GND
VDD → 3v3
SCL → D6
SDA → D7

it was okay at first.

Then what did you do?

it's my bad.

I used the 3v instead of 5v.

PrahastaGiri:
I used the 3v instead of 5v.

IMHO you should use 3.3V for a Nodemmcu.