SIM800l won't powered up

Hardware Arduino GSM Shield
1

Yesterday I tried to use SIM800l, but after wiring all the pins the led wasn't turn on (nor blinking). I set my arduino and SIM800l like this:

and uploaded some sample codes:

#include <SoftwareSerial.h>

SoftwareSerial SIM800L(2, 3); // RX | TX

char c = ' ';

void setup() 
{
    Serial.begin(9600);
    while(!Serial);
    Serial.println("Arduino with Module GSM is ready");
 
    SIM800L.begin(9600);  
    Serial.println("Module GSM started at 9600");
    delay(1000);
    Serial.println("Setup Complete! SIM800 is Ready!");
}
 
void loop()
{
    if (SIM800L.available()) { 
         c = SIM800L.read();
         Serial.write(c);
    }
 
    if (Serial.available()) { 
        c = Serial.read();
        SIM800L.write(c);  
    }
}

With those codes above, my serial monitor output stops at this point:

Arduino with Module GSM is ready 
Module GSM started at 9600
Setup Complete! SIM800 is Ready

<-- stops here, no further output

Can I get some clues what am I missed? Thanks