Air Quality Monitor (SEN0233) not working?

Dear DFRobot community,

so recently I bought the SEN0233 Air Quality Monitor. My hardware in this setup is: Arduino Uno R3, Gravity LCD1602 Module V1.1, Gravity IO Expansion Shield V7.1

When uploading the sample code provided

#include <Wire.h>
#include <SoftwareSerial.h>
#include "DFRobot_RGBLCD1602.h"

char col;
unsigned int PMSa = 0, FMHDSa = 0, TPSa = 0, HDSa = 0, PMSb = 0, FMHDSb = 0, TPSb = 0,
            HDSb = 0, PMS = 0, TPS = 0,  HDS = 0, CR1 = 0, CR2 = 0, FMHDS = 0;
unsigned char bufferRTT[32] = {}; //serial receive data
char tempStr[15];

SoftwareSerial mySerial(10, 11); // RX, TX

DFRobot_RGBLCD1602 lcd(/*RGBAddr*/0x6B ,/*lcdCols*/16,/*lcdRows*/2);  //16 characters and 2 lines of show

void setup()
{
 Serial.begin(115200);
 mySerial.begin(9600);
 lcd.init();//Initialize LCD1602 RGB display
 lcd.setRGB(0, 255, 0); //Set the initial backlight color of the display
 lcd.setCursor(0, 0 ); //Set displaying from (0, 0)
 lcd.print("T:");//Display T:
 lcd.setCursor(9, 0 );
 lcd.print("H:");
 lcd.setCursor(0, 1 );
 lcd.print("PM2.5:");
 lcd.setCursor(9, 1 );
 lcd.print("ug/m3");
}

void loop()
{
 while (mySerial.available() > 0) //Check whether there is any serial data
 {
   for (int i = 0; i < 32; i++) //Read serial data
   {
     col = mySerial.read();
     bufferRTT[i] = (char)col;
     delay(2);
   }

   mySerial.flush();
   CR1 = (bufferRTT[30] << 8) + bufferRTT[31];
   CR2 = 0;
   for (int i = 0; i < 30; i++)
     CR2 += bufferRTT[i];
   if (CR1 == CR2)               //Check
   {
     PMSa = bufferRTT[12];      //Read PM2.5 high 8-bit data
     PMSb = bufferRTT[13];      //Read PM2.5 low 8-bit data
     PMS = (PMSa << 8) + PMSb;   //PM2.5 data
     TPSa = bufferRTT[24];      //Read temperature high 8-bit data
     TPSb = bufferRTT[25];      //Read temperature low 8-bit data
     TPS = (TPSa << 8) + TPSb;   //Temperature data
     HDSa = bufferRTT[26];      //Read humidity high 8-bit data
     HDSb = bufferRTT[27];      //Read humidity low 8-bit data
     HDS = (HDSa << 8) + HDSb;   //Humidity data
   }
   else
   {
     PMS = 0;
     FMHDS = 0;
     TPS = 0;
     HDS = 0;
   }
 }
 lcd.setCursor(2, 0 );
 sprintf(tempStr, "%d%d.%d", TPS / 100, (TPS / 10) % 10, TPS % 10); //Display temperature
 lcd.print(tempStr);
 lcd.write(0xdf);              //Display °
 lcd.print('C');               //Display C
 lcd.setCursor(11, 0 );
 sprintf(tempStr, "%d%d.%d", HDS / 100, (HDS / 10) % 10, HDS % 10); //Display humidity
 lcd.print(tempStr);
 lcd.print('%');               //Display %
 lcd.setCursor(6, 1 );
 sprintf(tempStr, "%d%d%d", PMS / 100, (PMS / 10) % 10, PMS % 10); //Display PM2.5 ones, tens, hundreds unit ug/m³ 
 lcd.print(tempStr);
}
 

nothing appears on the LCD. Before programming, I set the switch to “Prog”, after the successful upload I set it to “Run”. Nothing happens, not even after resetting the Arduino.

After sending the sensor data to the Arduino IDE's serial monitor, it just displays a lot of 0s.

The sensor itself should be working, I hear a little fan inside. Also I wired everything accordingly to the documentation:

https://wiki.dfrobot.com/Air_Quality_Monitor__PM_2.5_Temperature_and_Humidity_Sensor__SKU__SEN0233

Did somebody experience the same problems? Do I overlook something? Any help is appreciated!