What am I doing wrong? (PHP and MYSQL) - php

Question

I have this code here which I have been using in several projects without any issue. The only thing i've changed is that I am using MAMP instead of XAMPP for this.
The problem I'm facing is the code runs without any errors (it runs through the if else statement in the login functions, but nothing happens (it doesn't redirect the user) and if I input wrong details it shows that no records are found. Can someone guide me through this please?
Login.php
<?php
session_start();
if (!empty($_SESSION['admin'])&&!empty($_SESSION['type'])) {
header("Location: admin/index.php");
}
elseif (!empty($_SESSION['user'])&&!empty($_SESSION['type'])) {
header("Location: user/");
}
?>
<!--===== LOGIN =====-->
<section id="login" class="padding" style="padding-top: 200px;">
<div class="container">
<div class="row">
<div class="col-md-12 text-center">
<div class="profile-login">
<div class="login_detail" style="margin-top:-50px;">
<!-- Tab panes -->
<div class="tab-content">
<h1>
<?php
extract($_POST);
if (isset($btn) && !empty($username) && !empty($password)) {
require 'includes/users.php';
login();
}
?>
</h1>
<div role="tabpanel" class="tab-pane fade in active" id="profile">
<h2>Login Below</h2>
<div class="agent-p-form">
<div class="row">
<form class="callus" action="login.php" method="POST">
<div class="col-md-12">
<div class="single-query">
<input name="username" type="text" class="keyword-input" placeholder="Username" required>
</div>
<div class="single-query">
<input name="password" type="password" class="keyword-input" placeholder="Password">
</div>
</div>
<div class="col-md-12 col-sm-12 col-xs-12 text-center">
<div class="query-submit-button">
<button name="btn" type="submit" class="btn_fill">Login</button>
</div>
</div>
</form>
Users.php
<?php
function login()
{
require 'connect.php';
$username = mysqli_real_escape_string($con,$_POST['username']);
$password = mysqli_real_escape_string($con,$_POST['password']);
$pass = $password;
$sql = "SELECT * FROM `users` WHERE `username`='$username' AND `password`='$pass'";
$query = mysqli_query($con,$sql);
$row = mysqli_num_rows($query);
if ($row == 0) {
echo "<b style='font-size:12px; color:#FFF'>Wrong Username/Password Combination</b>";
}
elseif ($row == 1) {
$fetch = mysqli_fetch_array($query);
$type = $fetch['user_role'];
$name = $fetch['username'];
if ($type == "Administrator") {
#session_start();
$_SESSION['user_role'] = $type;
$_SESSION['admin'] = $name;
header("Location: admin/index.php");
}
elseif ($type=="User") {
#session_start();
$_SESSION['user_role'] = $type;
$_SESSION['user'] = $name;
header("Location: user/");
}
else{
echo "<b>Error</b>";
}
}
else{
echo "<b>Error</b>";
}
}

Answer 1

Fixed it: The problem was with the header.. it was not loading it because the output was already started, the solution was to group all the PHP at the start of the page and put the include partial/header at the very bottom of the php so that no whitespace or output can be read before the header executes.. thus the script works perfectly now, I wish to thank you all for giving me guidance to get to this desired solution!
<?php
session_start();
if (!empty($_SESSION['admin'])&&!empty($_SESSION['type'])) {
header("Location: admin/");
}
elseif (!empty($_SESSION['user'])&&!empty($_SESSION['type'])) {
header("Location: user/");
}
extract($_POST);
if (isset($btn) && !empty($username) && !empty($password)) {
require 'includes/users.php';
login();
}
include "partials/header.php";
?>

Answer 2

You already start a session in Login.php. Please remove #session_start(); from Users.php.