I'm trying to post some data to PHP through postman, I set up everything with all required fields and their values but for some reason when I try to post data, it says that field is empty even though I set the value in post man request.
  <?php 
   include_once 'creds.php';
   $con  =  mysqli_connect(DB_HOST,DB_USER,DB_PASSWORD,DB_NAME);
   if($con -> connect_error){
     echo "Failed connecting to database".mysqli_connect_errno();
   } else {
    echo "Success connecting\n";
  }
  
    //Register User
    if($_SERVER['REQUEST_METHOD'] == 'POST'){
  
       if(!isset($username)){
          echo "Username field cannot be empty\n";
          return;
       }
       if(!isset($password)){
          echo "password field cannot be empty\n";
          return;
       }
       if(!isset($email)){
          echo "Email field cannot be empty\n";
          return;
       }
     
      $username = $_POST['username'];
      $password = $_POST['password'];
      $email = $_POST['email'];
       
        $stmt = $con->prepare("INSERT INTO `shop`(`userID`, `username`, `email`, `password`) VALUES (?,?,?,?)");
        $stmt-> bind_param("sss",$username,$password,$email);
        if($stmt -> execute()){
           echo "Succesfully Registered";
         } else {
           echo "Failure\n".mysqli_error($con);
         }
      } 
?>
- This is screenshot of Postman request

 
     
    