[HELP] SIM800L cannot send SMS

Good day,

I have a problem with my SIM800L, it cannot send SMS. I have made basic troubleshooting: Pins, Code, SIM card credit, etc. Everything appears to be fine, but it is still not working.

Once I run that code below and send s on the serial monitor, its returns gibberish. I tried switching RX and TX pins but to no avail.

Please help.

#include <SoftwareSerial.h>

SoftwareSerial mySerial(2, 3);

void setup()
{
  mySerial.begin(9600);   // Setting the baud rate of GSM Module  
  Serial.begin(9600);    // Setting the baud rate of Serial Monitor (Arduino)
  delay(100);
}


void loop()
{
  if (Serial.available()>0)
   switch(Serial.read())
  {
    case 's':
      Serial.println("Pressed S");
      SendMessage();
      break;
    case 'r':
      RecieveMessage();
      break;
  }

 if (mySerial.available()>0)
   Serial.write(mySerial.read());
}


 void SendMessage()
{
  mySerial.println("AT+CMGF=1");    //Sets the GSM Module in Text Mode
  delay(1000);  // Delay of 1000 milli seconds or 1 second
  mySerial.println("AT+CMGS=\"+63966419xxxx\"\r"); // Replace x with mobile number
  delay(1000);
  mySerial.println("I am SMS from GSM Module");// The SMS text you want to send
  delay(100);
   mySerial.println((char)26);// ASCII code of CTRL+Z
  delay(1000);
}


 void RecieveMessage()
{
  mySerial.println("AT+CNMI=2,2,0,0,0"); // AT Command to receive a live SMS
  delay(1000);
 }

You may need to send the Sim800L an initial “AT” then a delay to synchronise the modules, put that and also "AT+CMGF=1"in the Setup.

When you say that you have done basic troubleshooting, does this include loading a simple Serial Relay / Repeater sketch onto the Arduino and seeing what the response to each AT command is?