The problem with the Modbus library and MAX485

I am a beginner in Arduino
I am using the Modbus library Modbus Library and I want to use the sample project from the library.

This code compile succesfull

#include <SimpleModbusSlave.h>

#define  LED 9  


unsigned int holdingRegs[HOLDING_REGS_SIZE]; 

void setup()
  modbus_configure(&Serial, 9600, SERIAL_8N2, 1, 2, HOLDING_REGS_SIZE, holdingRegs);
  modbus_update_comms(9600, SERIAL_8N2, 1);
    pinMode(LED, OUTPUT);

void loop()
  holdingRegs[ADC_VAL] = analogRead(A0); 
  analogWrite(LED, holdingRegs[PWM_VAL]>>2);   


When i upload this code to arduino i giving error like this:

avrdude: stk500_getsync(): not in sync: resp=0x00

To connect the Arduino using the Modbus protocol with Laptop i use Converter rs485 to USB (pic related)

Converter ch340

if i unplug Converter it's giving that same error.

Please tell me, what im doing wrong?

Hi, Try to disconnect from arduino Pin 0 and Pin 1 while you upload the new program from Arduino Ide

Thanks for the reply. I did this and now upload correctly.
Unfortunately, I now have another problem. I used a program modscan64 to test communication. I get the message:

** MODBUS Message TIME-OUT **

Screenshot Modscan64 with my configuration

This is the Device Manager:
COM Ports

What am I doing wrong?