The Error is:
Fatal error: Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ':rafli_namaUser, :rafli_username, :rafli_password)' at line 2 in C:\xampp\htdocs\rafli_kasir\rafli_register.php:16 Stack trace: #0 C:\xampp\htdocs\rafli_kasir\rafli_register.php(16): mysqli->prepare('INSERT INTO raf...') #1 {main} thrown in C:\xampp\htdocs\rafli_kasir\rafli_register.php on line 16
cannot find any solution after research, this is my code:
<?php
require_once("rafli_koneksi.php");
if(isset($_POST['rafli_register'])){
    $rafli_namaUser = filter_input(INPUT_POST, 'rafli_namaUser', FILTER_SANITIZE_STRING);
    $rafli_username = filter_input(INPUT_POST, 'rafli_username', FILTER_SANITIZE_STRING);
    $rafli_password = password_hash($_POST["rafli_password"], PASSWORD_DEFAULT);
    $sql = "INSERT INTO rafli_user (rafli_namaUser, rafli_username, rafli_password) 
            VALUES (:rafli_namaUser, :rafli_username, :rafli_password)";
    $stmt = $rafli_conn->prepare($sql);
    $params = array(
        ":rafli_namaUser" => $rafli_namaUser,
        ":rafli_username" => $rafli_username,
        ":rafli_password" => $rafli_password
    );
    $saved = $stmt->execute($params);
    if($saved) header("Location: rafli_login.php");
}
?>
rafli_koneksi.php
<?php
$rafli_host = "localhost";
$rafli_username = "root";
$rafli_password = "";
$rafli_database = "rafli_kasir";
$rafli_conn = new mysqli( $rafli_host, $rafli_username, $rafli_password, $rafli_database );
    echo 'Gagal terhubung ke database';
} else {
    // Koneksi berhasil
}
?>