led strip WS2812B - bluetooth HC-05 - mobile App- String,substring,toInt,

Hello everyone,
I am trying to change the colour of led strip WS2812B using smartphone app, bluetooth module HC-05 and FastLed library.
Example of received string from App: 4A255S149D136F
I extracted each colour of RGB led strip using substring function and changed to int.
And after the colour update led strip doesn’t change, blink or went off.

I will be very greatful if someone look at my code and give me advice what I can do (void pixel_colour() section).

Bluetooth baud rate and voltages to RX, TX seems to be ok. ON and OFF buttons in the App works fine.

I tried so many approachings to the problem and finish with code below:

#include <FastLED.h>
#include <SoftwareSerial.h>

#define NUM_LEDS 6
#define DATA_PIN 5
#define COLOR_ORDER GRB
#define LED_TYPE WS2812B

CRGB leds[NUM_LEDS];

SoftwareSerial Bluetooth(53, 52);
int brightness = 200;
String dataI = "";
char dataIn;
int valG = 100;
int valR = 100;
int valB = 100;

void setup() {
  delay(30);
  FastLED.addLeds<LED_TYPE, DATA_PIN, COLOR_ORDER>(leds, NUM_LEDS);
  FastLED.setBrightness (brightness);
  Serial.begin(9600);
  Bluetooth.begin(9600);
}
void loop() {
  if (Serial.available() > 0) {
    dataIn = Serial.read();
    Serial.println(dataIn);
    delay(20);

    if (dataIn == '1') {
      delay(10);
      for (int fullStrip = 0; fullStrip <= NUM_LEDS - 1; fullStrip++) {
        leds[fullStrip] = CRGB(valR, valG, valB);
      }
    }
    else if (dataIn == '2') {
      delay(10);
      for (int fullStrip = 0; fullStrip <= NUM_LEDS - 1; fullStrip++) {
        leds[fullStrip] = CRGB(0, 0, 0);
      }
    }
    FastLED.show();
    delay(30);
  }
}
void pixel_colour() {
  while (Serial.available() > 0) {
    dataI = Serial.readString();
    delay(20);

    if (dataI.startsWith("4")) {
      String G = dataI.substring(dataI.indexOf("A") + 1, dataI.indexOf("S"));
      valG = G.toInt();
      String R = dataI.substring(dataI.indexOf("S") + 1, dataI.indexOf("D"));
      valR = R.toInt();
      String B = dataI.substring(dataI.indexOf("D") + 1, dataI.indexOf("F"));
      valB = B.toInt();
    }
    for (int fullStrip = 0; fullStrip <= NUM_LEDS - 1; fullStrip++) {
      leds[fullStrip] = CRGB(valG, valR, valB);
    }
    FastLED.show();
    delay(30);
  }
}

Anyone??

It looks as I made simple mistake but I can't figured out what is wrong.

Please ask if you need more information.

Even advice how to easily check what code is received by led strip will help.

Thank you.

i would suggest you test your calls to CRGB with hardcoded values to make sure you're passing good data

        leds[fullStrip] = CRGB(0, 0, 0);