E-commerce site problem

hello I have filled in manually but nothing to do. I tried redefining the recheck form but nothing. as if there was an empty field that I can't see.

?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

include 'includes/session.php';

if(isset($_POST['signup'])){
$firstname = $_POST['firstname'];
$lastname = $_POST['lastname'];
$email = $_POST['email'];
$password = $_POST['password'];
$repassword = $_POST['repassword'];

$_SESSION['firstname'] = $firstname;
$_SESSION['lastname'] = $lastname;
$_SESSION['email'] = $email;

if(!isset($_SESSION['captcha'])){
require('recaptcha/src/autoload.php');
$recaptcha = new \ReCaptcha\ReCaptcha('6LevO1IUAAAAAFCCiOHERRXjh3VrHa5oywciMKcw', new \ReCaptcha\RequestMethod\SocketPost());
$resp = $recaptcha->verify($_POST['g-recaptcha-response'], $_SERVER['REMOTE_ADDR']);

if (!$resp->isSuccess()){
$_SESSION['error'] = 'Please answer recaptcha correctly';
header('location: signup.php');
exit();
}
else{
$_SESSION['captcha'] = time() + (10*60);
}

}

if($password != $repassword){
$_SESSION['error'] = 'Passwords did not match';
header('location: signup.php');
}
else{
$conn = $pdo->open();

$stmt = $conn->prepare("SELECT COUNT(*) AS numrows FROM users WHERE email=:email");
$stmt->execute(['email'=>$email]);
$row = $stmt->fetch();
if($row['numrows'] > 0){
$_SESSION['error'] = 'Email already taken';
header('location: signup.php');
}
else{
$now = date('Y-m-d');
$password = password_hash($password, PASSWORD_DEFAULT);

//generate code
$set='123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$code=substr(str_shuffle($set), 0, 12);

try{
$stmt = $conn->prepare("INSERT INTO users (email, password, firstname, lastname, activate_code, created_on) VALUES (:email, :password, :firstname, :lastname, :code, :now)");
$stmt->execute(['email'=>$email, 'password'=>$password, 'firstname'=>$firstname, 'lastname'=>$lastname, 'code'=>$code, 'now'=>$now]);
$userid = $conn->lastInsertId();

$message = "

Thank you for Registering.

Your Account:
Email: ".$email."
Password: ".$_POST['password']."
Please click the link below to activate your account.
Activate Account
";

//Load phpmailer
require 'vendor/autoload.php';

$mail = new PHPMailer(true);
try {
//Server settings
$mail->isSMTP();
$mail->Host = 'smtp.gmail.com';
$mail->SMTPAuth = true;
$mail->Username = 'testsourcecodester@gmail.com';
$mail->Password = 'mysourcepass';
$mail->SMTPOptions = array(
'ssl' => array(
'verify_peer' => false,
'verify_peer_name' => false,
'allow_self_signed' => true
)
);
$mail->SMTPSecure = 'ssl';
$mail->Port = 465;

$mail->setFrom('testsourcecodester@gmail.com');

//Recipients
$mail->addAddress($email);
$mail->addReplyTo('testsourcecodester@gmail.com');

//Content
$mail->isHTML(true);
$mail->Subject = 'ECommerce Site Sign Up';
$mail->Body = $message;

$mail->send();

unset($_SESSION['firstname']);
unset($_SESSION['lastname']);
unset($_SESSION['email']);