Redirect loop issue in PHP website

Question

I have been working on CS50's problem set 7, in which we have to make a financial website using MVC. I completed the website and it is working absolutely fine on my local machine.

But when I upload the files to hosting (free) service's server and try to access it I get a Redirect Loop error. Here is the link to it: http://ghazilajpal.byethost6.com/finance/public/

Here is code of login.php:

<?php

    // configuration
    require("../includes/config.php"); 

    // if user reached page via GET (as by clicking a link or via redirect)
    if ($_SERVER["REQUEST_METHOD"] == "GET")
    {
        // render form
        render("login_form.php", ["title" => "Log In"]);
    }

    // else if user reached page via POST (as by submitting a form via POST)
    else if ($_SERVER["REQUEST_METHOD"] == "POST")
    {
        // validate submission
        if (empty($_POST["username"]))
        {
            apologize("You must provide your username.");
        }
        else if (empty($_POST["password"]))
        {
            apologize("You must provide your password.");
        }

        // query database for user
        $rows = query("SELECT * FROM users WHERE username = ?", $_POST["username"]);

        // if we found user, check password
        if (count($rows) == 1)
        {
            // first (and only) row
            $row = $rows[0];

            // compare hash of user's input against hash that's in database
            if (crypt($_POST["password"], $row["hash"]) == $row["hash"])
            {
                // remember that user's now logged in by storing user's ID in session
                $_SESSION["id"] = $row["id"];
                $_SESSION["cash"] = $row["cash"];
                // redirect to index.php (portfolio)
                redirect("/");
            }
        }

        // else apologize
        apologize("Invalid username and/or password.");
    }

?>

Update

Here is login_form.php:

<form action="login.php" method="post">
    <fieldset>
        <div class="form-group">
            <input autofocus class="form-control" name="username" placeholder="Username" type="text"/>
        </div>
        <div class="form-group">
            <input class="form-control" name="password" placeholder="Password" type="password"/>
        </div>
        <div class="form-group">
            <button type="submit" class="btn btn-default">Log In</button>
        </div>
    </fieldset>
</form>
<div>
    or <a href="register.php">register</a> for an account
</div>

And this is config.php. This also has a redirect:

<?php

    /**
     * config.php
     *
     * Computer Science 50
     * Problem Set 7
     *
     * Configures pages.
     */

    // display errors, warnings, and notices
    ini_set("display_errors", true);
    error_reporting(E_ALL);

    // requirements
    require("constants.php");
    require("functions.php");

    // enable sessions
    session_start();

    // require authentication for all pages except /login.php, /logout.php, and /register.php
    if (!in_array($_SERVER["PHP_SELF"], ["/login.php", "/logout.php", "/register.php"]))
    {
        if (empty($_SESSION["id"]))
        {
            redirect("login.php");
        }
    }

?>

I hope its easy to understand. I don't know where the problem lies and how to fix it.

I could have asked it on cs50.stackexchange.com but a similar question is already there with no answer.

Answer 1

I did some debugging using bhushanRJ's advice of using die (). And found out that the issue is with URLs. So using /finance/public/login.php instead of just login.php (same for other array items) solved the issue.

However CSS and JS files weren't loading. Similarly, fixing their URLs in templates fixed the issue.