Unable to read values from multiple modbus RTU sensors (XY-MD02)

[temperate]

I've been trying to interface XY-MD02 sht20 sensors to an opta plc. There are no problems when i use only one sensor but when i try to use two only one of them works the other one prints "Response not from requested slave"

/**
  Getting Started with Modbus RTU on Opta™
  Name: Opta_Client
  Purpose: Writes Coil and Holding Register values; Reads Coil, Discrete Input, Holding Registers, and Input Register values.

  @author Arduino
*/

#include <ArduinoModbus.h>
#include <ArduinoRS485.h>  // ArduinoModbus depends on the ArduinoRS485 library
#include "OptaBlue.h"
//RTU SLAVES
//Inlet SHT
#define SLAVE_ID1 1
#define FUNC_ADD1 3
#define START_ADD1 0x01
#define READ_REG1 2
#define CALIB_H1 0
#define CALIB_T1 0
//Outlet SHT
#define SLAVE_ID2 3
#define FUNC_ADD2 3
#define START_ADD2 0x01
#define READ_REG2 2
#define CALIB_H2 12
#define CALIB_T2 -3

using namespace Opta;

constexpr auto baudrate{ 9600 };

// Calculate preDelay and postDelay in microseconds as per Modbus RTU Specification
// MODBUS over serial line specification and implementation guide V1.02
// Paragraph 2.5.1.1 MODBUS Message RTU Framing
// https://modbus.org/docs/Modbus_over_serial_line_V1_02.pdf
constexpr auto bitduration{ 1.f / baudrate };
constexpr auto preDelayBR{ bitduration * 9.6f * 3.5f * 1e6 };
constexpr auto postDelayBR{ bitduration * 9.6f * 3.5f * 1e6 };
//constexpr auto preDelayBR { bitduration * 10.0f * 3.5f * 1e6 };

//Relays
int R1 = 0;
int D1608E_R1 = 0;
//sensor readings memory
float temperature = 0;
float temperature1 = 0;
float humidity = 0;
float humidity1 = 0;

void setup() {
  Serial.begin(9600);


  Serial.println("Modbus RTU Client");

  RS485.setDelays(preDelayBR, postDelayBR);

  // Start the Modbus RTU client
  if (!ModbusRTUClient.begin(baudrate, SERIAL_8N1)) {
    Serial.println("Failed to start Modbus RTU Client!");
    while (1)
      ;
  }

  pinMode(LED_D0, OUTPUT);
  pinMode(R1, OUTPUT);
  pinMode(D1608E_R1, OUTPUT);
  OptaController.begin();
  delay(1000);
}

void loop() {
  DigitalMechExpansion mechExp = OptaController.getExpansion(0);
  mechExp.updateDigitalInputs();
  // if (currentSensor == 1) {
  Serial.println("==============================================================================================================================================");
  Serial.println("INPUT");
  readAndPrintRegisterValues(SLAVE_ID1, START_ADD1, READ_REG1, "Inlet temperature", "Inlet Humidity", temperature1, humidity1, CALIB_H1, CALIB_T1);  // Slave ID 1
  delay(100);
  readAndPrintRegisterValues(SLAVE_ID2, START_ADD2, READ_REG2, "Outlet temperature", "Outlet Humidity", temperature, humidity, CALIB_H2, CALIB_T2);  // Slave ID 2
  Serial.println("==============================================================================================================================================");
  Serial.println("OUTPUT");
  if (humidity1 >= 65) {
    digitalWrite(R1, HIGH);
    digitalWrite(LED_D0, HIGH);
    Serial.print("R1: ON , ");
  } else if (humidity1 <= 65) {
    digitalWrite(R1, LOW);
    digitalWrite(LED_D0, LOW);
    Serial.print("R1: OFF, ");
  }
  if (temperature1 >= 32) {
    mechExp.digitalWrite(D1608E_R1, HIGH);
    Serial.println(" D1608E_R1: ON ");
  } else if (temperature1 <= 32) {
    mechExp.digitalWrite(D1608E_R1, LOW);
    Serial.println(" D1608E_R1: OFF");
  }
  mechExp.updateDigitalOutputs();
  delay(1000);
}


/**
  Reads Input Register values from the server under specified address.
*/
void readAndPrintRegisterValues(uint8_t slaveId, uint16_t startAddress, uint16_t numRegisters, const char* tempLabel, const char* humLabel, float& temp, float& hum, float hum_calib, float temp_calib) {
  Serial.print("Reading input register values SLAVE ID: ");
  Serial.print(slaveId);
  Serial.println(" ... ");

  // Request data from the specified slave ID
  if (!ModbusRTUClient.requestFrom(slaveId, INPUT_REGISTERS, startAddress, numRegisters)) {
    error++;
    Serial.print("failed! ");
    Serial.println(ModbusRTUClient.lastError());
    return;

  }

  // Check if enough data is available
  if (ModbusRTUClient.available() >= numRegisters) {
    uint16_t firstRegister = ModbusRTUClient.read();   //Read temperature
    uint16_t secondRegistor = ModbusRTUClient.read();  //Read humidity

    // Convert raw values to readable values
    float temperature = firstRegister / 10.0;  // Scale by 10 if required
    float humidity = secondRegistor / 10.0;    // Scale by 10 if required
    temp = temperature;
    hum = humidity;
    if (hum > 100) {
      hum = hum - 100;
    }
    hum = hum + hum_calib;
    temp = temp + temp_calib;
    // Print the converted values
    Serial.print(tempLabel);
    Serial.print(": ");
    Serial.print(temp);
    Serial.print(" °C, ");

    Serial.print(humLabel);
    Serial.print(": ");
    Serial.println(hum);
  } else {
    Serial.println("Insufficient data received!");
  }
  Serial.println("");
}

The interesting thing is that the issue is only with the slave ID which is called firsi.e., readAndPrintRegisterValues(SLAVE_ID1, START_ADD1, READ_REG1, "Inlet temperature", "Inlet Humidity", temperature1, humidity1, CALIB_H1, CALIB_T1); // Slave ID 1 t which means its not a sensor issue (and yes, both of them work in individual code)
the connection of A and B lines is standard with common ground and separate power sources.
Can someone please figure out what the issue might be?