登录后登录代码不将用户重定向到成功页面

Question

成功登录后，我的登录页面（我想）不会重定向到受限页面...

<?php
session_start();


include('incs/database/dbconfig.php');

//check to know if login button is set/click
if(isset($_POST["loginBtn"])) 
{
$username=$_POST['username'];
$password=md5($_POST['password']);
$sql = "SELECT * FROM users WHERE userName ='$username' AND userPass ='$password'";
  $result = mysqli_query($dbconn,$sql);
  $row = mysqli_fetch_array($result);
  if($row) {
      $_SESSION["userid"]= $row["uid"];

      if(!empty($_POST["remember"])) {
        setcookie ("user_login",$_POST["username"],time()+ (10 * 365 * 24 * 60 * 60));
        setcookie ("userpassword",$_POST["password"],time()+ (10 * 365 * 24 * 60 * 60));
      } else {
        if(isset($_COOKIE["user_login"])) {
          setcookie ("user_login","");
        }
        if(isset($_COOKIE["userpassword"])) {
          setcookie ("userpassword","");
        }
      }
      header('Location: user/welcome.php');
  } else {
    $loginError = '<div class="alert alert-success fade in">
                  <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                  <strong>Success!</strong> This alert box could indicate a successful or positive action.
                </div>';
  }
}
?>

我希望在登录表单处理之后，它应该重定向到welcome.php页面。但是我得到的结果是：虽然它没有显示任何错误，但是它使bacck返回到登录页面