Blynk not turning the LED ON on NodeMCU

Question

I have connected an LED to my NodeMCU in the following way: Circuit Diagram and have successfully controlled it using the serial port of my laptop. Now I want to control it remotely through Wifi and Blynk App on my phone. I have added all the required specifications like board type and pin number etc. in the app. I have been able to send the LDR data successfully to ThingSpeak site, which means the connection of NodeMCU to the wifi is fine. But when I turn ON the light using button on Blynk App, the LED lights up for less than a second and then turns off. The serial monitor on Arduino IDE keeps showing the light is off. Here is the code that I uploaded on NodeMCU:

#include <ThingSpeak.h>
#include <ESP8266WiFi.h>
#define BLYNK_PRINT Serial
#include <BlynkSimpleEsp8266.h>

const char* ssid = "WifiName";
const char* password = "WifiPassword";
char auth[] = "AuthCode from Blynk App";

const int ldrPin = A0;
int ldrVal = 0;
int inputVal = 0;
const int ledPin = 5; //D1 pin on NodeMCU

WiFiClient client;
long myChannelNumber = ThingSpeak channel number;
const char myWriteApiKey[] = "Thingspeak write api key";

void setup() {
  Serial.begin(9600);
  Blynk.begin(auth, ssid, password);
  delay(100);
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, 0);
  pinMode(ldrPin, INPUT);

  Serial.println();
  Serial.println();
  Serial.print("Connecting To: ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);
  while(WiFi.status() != WL_CONNECTED){
    delay(200);
    Serial.println("...");
  }

  Serial.println("");
  Serial.println("Wifi Connected");
  Serial.print("Ip Address: ");
  Serial.println(WiFi.localIP());
  ThingSpeak.begin(client);
}

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

  while(Serial.available()>0){
    inputVal = Serial.read();
  }
  ldrVal = analogRead(ldrPin);
  Serial.println(ldrVal);
  
  if(inputVal=='1'){
    digitalWrite(ledPin, HIGH);
    Serial.println("ON");
  }
  else{ 
    digitalWrite(ledPin, LOW);
    Serial.println("OFF");
  }
  Serial.println("");
  ThingSpeak.writeField(myChannelNumber, 1, ldrVal, myWriteApiKey);
  ThingSpeak.writeField(myChannelNumber, 2, inputVal, myWriteApiKey);

}

I have added Blynk Functionality to the already running code of my project where I take input from serial port and turn the LED on or off based on that input. Why is the LED not turning on properly?