Need help with dimmer project arduino uno , wemos d1 mini

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

char auth[] = "xxx"; //WeMos D1 Mini 
char ssid[] = "xxx";
char password[] = "xxx";

IPAddress server_ip (192, 168, 1, 154);

// Mac address should be different for each device in your LAN
IPAddress arduino_ip ( 192,   168,   1,  154);
IPAddress dns_ip     (  8,   8,   8,   8);
IPAddress gateway_ip ( 192,   168,   1,   1);
IPAddress subnet_mask(255, 255, 255,   0);

SimpleTimer timer;
#define UPButton D5  // Set increment button pin.
#define DNButton D6 // Set decrement button pin.
#define WLED D7  // Set LED pin.
int brightness = 0;  // Start on with LED on.
SimpleTimer timerBUTTONS;  // Setup timerBUTTONS to check buttons.
/////////////////////////////////////////////////

void setup()
{
  pinMode(UPButton, INPUT_PULLUP);  // Set increment button pin to INPUT - Add _PULLUP if not already set in hardware.
  pinMode(DNButton, INPUT_PULLUP);  // Set decrement button pin to INPUT - Add _PULLUP if not already set in hardware.

  Serial.begin(115200);
  Serial.println();
  WiFi.config(arduino_ip, gateway_ip, subnet_mask);
  WiFi.begin(ssid, password);
  Blynk.config(auth);
  while (Blynk.connect(1000) == false) {
  }


  timerBUTTONS.setInterval(100L, whiteLED);  // Timer to run whiteLED function every half second.
}

////////////////////////////////////////////////

BLYNK_WRITE(V0) // Slider Widget Function - runs every-time slider widget is physically moved.
{
  brightness = param.asInt();  // Get slider value.
  analogWrite(WLED, brightness);  // Send slider value to LED
Serial.print("Slider: ");
Serial.println(brightness);
}


/////////////////////////////////////////////////

void whiteLED() // This function checks buttons status and updates White LED and slider (frequency dependent on timer).
{
  // Check increment button and respond.
  if (digitalRead(UPButton) == LOW and brightness < 1023) {  // Only do something if button pressed and brightness counter in range.
    brightness += 10;  // Increment counter by 50
    Blynk.virtualWrite(V0, constrain(brightness, 0, 1023));  // Send feedback to Slider Widget - but keep within 0-255
   analogWrite(WLED, constrain(brightness, 0, 1023));  // Send data to LED - but keep within 0-255
Serial.print("Button: ");
Serial.println(brightness);
    Serial.print(brightness);
  }
  // Check decrement button and respond..
  else if (digitalRead(DNButton) == LOW and brightness > 0) {  // Only do something if button pressed and brightness counter in range.
    brightness -= 10;  // Decrement counter by 50
    Blynk.virtualWrite(V0, constrain(brightness, 0, 1023));  // Send feedback to Slider Widget - but keep within 0-255
   analogWrite(WLED, constrain(brightness, 0, 1023));  // Send data to LED - but keep within 0-255
Serial.print("Button: ");
Serial.println(brightness);
    Serial.print(brightness);
  }
  else { // nothing happening here... move along :)
  }
}

/////////////////////////////////////////////////
/////////////////////////////////////////////////

void loop()
{
  Blynk.run();  // Runs usual Blynk routine.
  timerBUTTONS.run();  // Checks timer and runs whiteLED function.
}