GPS/GPRS/GSM Module V3.0 can't send a message

Hello

I am new to developing with Arduino,
But I'm doing a project for a university course,

I need to capture the current location and sends it via sms.

For this, I bought a GPS / GPRS / GSM Shield V3.0 (SKU: TEL0051) shield and an Arduino Uno.

I used the examples described in GPS_GPRS_GSM_Module_V3.0__SKU_TEL0051_-DFRobot

But I could not send sms or make calls.
DFRobot lights are on and the Serial Monitor can monitor the correct commands

Anyone know a solution?
Or problem that may be causing this?

// Product name: GPS/GPRS/GSM Module V3.0
// # Product SKU : TEL0051
// # Version     : 0.1
 
// # Description:
// # The sketch for driving the gsm mode via the Arduino board
 
// # Steps:
// #        1. Turn the S1 switch to the Prog(right side)
// #        2. Turn the S2 switch to the Arduino side(left side)
// #        3. Set the UART select switch to middle one.
// #        4. Upload the sketch to the Arduino board
// #        5. Turn the S1 switch to the comm(left side) 
// #        6. RST the board 
 
// #        wiki link- http://www.dfrobot.com/wiki/index.php/GPS/GPRS/GSM_Module_V3.0_(SKU:TEL0051)
 
byte gsmDriverPin[3] = {
  3,4,5};//The default digital driver pins for the GSM and GPS mode
//If you want to change the digital driver pins
//or you have a conflict with D3~D5 on Arduino board,
//you can remove the J10~J12 jumpers to reconnect other driver pins for the module!
void setup()
{    
  //Init the driver pins for GSM function
  for(int i = 0 ; i < 3; i++){
    pinMode(gsmDriverPin[i],OUTPUT);
  }
  digitalWrite(5,HIGH);//Output GSM Timing 
  delay(1500);
  digitalWrite(5,LOW);  
  digitalWrite(3,LOW);//Enable the GSM mode
  digitalWrite(4,HIGH);//Disable the GPS mode
  delay(2000);
  Serial.begin(9600); //set the baud rate
  delay(5000);//call ready
  delay(5000);
  delay(5000);
}
 
void loop()
{  
  Serial.println("AT"); //Send AT command  
  delay(2000);
  Serial.println("AT");   
  delay(2000);
  //Send message
  Serial.println("AT+CMGF=1");
  delay(1000);
  Serial.println("AT+CMGS=\"15800449871\"");//Change the receiver phone number
  delay(1000);
  Serial.print("HELLO");//the message you want to send
  delay(1000);
  Serial.write(26);
  while(1);
}

Are you giving power via arduino to the shield? Then you have to use external power source. GSM shield may use upto 2A. Power the GSM shield separately.