Read SMS using SIM800L and Print the message content in I2C LCD Display .

ReadSMS.ino

#include <SoftwareSerial.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

String Grsp;


SoftwareSerial mySerial(3, 2); //SIM800L Tx & Rx is connected to Arduino #3 & #2

void setup()
{
  //Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
  Serial.begin(9600);

  lcd.begin();
  lcd.setCursor(0, 0);
  lcd.print("Data");

  //Begin serial communication with Arduino and SIM800L
  mySerial.begin(9600);

  Serial.println("Initializing...");
  delay(1000);

  mySerial.println("AT"); //Once the handshake test is successful, it will back to OK
  updateSerial();
  mySerial.println("AT+CSQ"); //Signal quality test, value range is 0-31 , 31 is the best
  updateSerial();
  mySerial.println("AT+CCID"); //Read SIM information to confirm whether the SIM is plugged
  updateSerial();
  mySerial.println("AT+CREG?"); //Check whether it has registered in the network
  updateSerial();

  mySerial.println("AT+CMGF=1"); // Configuring TEXT mode
  updateSerial();
  mySerial.println("AT+CNMI=1,2,0,0,0"); // Decides how newly arrived SMS messages should be handled
  updateSerial();

}

void loop()
{
  updateSerial();


}

void updateSerial()
{

  delay(500);
  while (Serial.available())
  {
    mySerial.write(Serial.read());//Forward what Serial received to Software Serial Port

  }
  while (mySerial.available())
  {
    //Serial.write(mySerial.read());
    String sms = mySerial.readString();
    Serial.println(sms);
    int index = sms.indexOf(';');
    String message = sms.substring(index);
    Serial.println("Message is :" + message );
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Data");
    lcd.setCursor(0, 1);
    lcd.print(message);



  }
}

hi . the code does not work for me . it always shows : massage is : . and nothing print for massage . what should i do to detect the recieved massage ?