无法使用标题重定向特定页面（“位置：../ custom.php？error = emptyfields＆uid =。$ username."&mail=".$email”）; [重复]

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I'm creating a login/signup page. Where when designing a signup's full Php code I incur a problem where when using header() function in PHP it is not redirecting to other pages. It is always loading the same page. Means, if I am on page 'signup.inc.php' and my header() wants to redirect to header("Location: ../signup.php?error=emptyfields"); it loads to 'signup.inc.php' page again. [Note: my signup.php page is in a folder named as 'includes' that's why I used ../]

I tried using ob_start(); and checked for any white spaces if any but nothing seems to work.

<?php
if(!isset($_POST['signup-submit'])){
    require 'dbh.inc.php';

    $username =$_POST['uid'];
    $email =$_POST['mail'];
    $password =$_POST['pwd'];
    $passwordRepeat =$_POST['pwd-repeat'];

    if(empty($username) || empty($email) || empty($password) || 
empty($passwordRepeat)){
        header("Location: ../signup.php? 
error=emptyfields&uid=".$username."&mail=".$email);
        exit();
    }

I expect the output to be 'localhost/signup.php?error=emptyfields&uid=".$username."&mail=".$email' but the output is 'localhost/signup.inc.php'enter code here

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