validasi login dengan php

?php include 'config.php'; session_start(); if (isset($_SESSION['username'])) { header("Location: berhasil_login.php"); exit(); } if (isset($_POST['submit'])) { $email = mysqli_real_escape_string($conn, $_POST['email']); $password = hash('sha256', $_POST['password']); // Hash the input password using SHA-256 $sql = "SELECT * FROM users WHERE ... tidak bisa login gmail di hp