My php file which is online with Hostinger is not working even though it works perfectly fine on XAMPP

Ive been developing this project for a while and after finishing developing it on my local server I uploaded it to Hostinger. However now the inc files whic process the users input wont work. Ive checked and the database connection has the correct credentials.

Ive added in var_dumps to show that it is correctly taking in the data

https://emilyanddavid2025.co.uk/02_guest_login.php

<?php

if ($_SERVER["REQUEST_METHOD"] === "POST") {

    $username = $_POST["username"]; // ADD FEATURE TO SANITIZE THE USER INPUT TO PREVENT ATTACKS
    
    var_dump($username);

    try {
        
        require_once 'dbh.inc.php';
        require_once 'guest_login_model.inc.php';
        // VIEW WOULD GO HERE IF NEEDED
        require_once 'guest_login_contr.inc.php';

        $errors = [];

        if (is_input_empty($username)) {
            $errors["empty_input"] = "Fill in username!";
        }

        $result = get_user($pdo, $username);
        
        var_dump($result);

        if (!isset($errors["empty_input"])) {
            if (is_username_wrong($result)) {
                $errors["login_incorrect"] = "Incorrect username!";
            }
        }

        require_once 'config_session.inc.php';

        if ($errors) {
            $_SESSION["errors_login"] = $errors;

            header("location: ../02_guest_login.php");
            die();
        }

        $newSessionId = session_create_id();
        $sessionId = $newSessionId . "_" . $result["id"];
        session_id($sessionId);

        $_SESSION["user_id"] = $result["id"];
        $_SESSION["user_username"] = htmlspecialchars($result["username"]);
        $_SESSION["user_guest_one"] = htmlspecialchars($result["guest_one"]);
        $_SESSION["user_guest_two"] = htmlspecialchars($result["guest_two"]);
        $_SESSION["user_guest_three"] = htmlspecialchars($result["guest_three"]);
        $_SESSION["user_guest_four"] = htmlspecialchars($result["guest_four"]);
        $_SESSION["last_regeneration"] = time();
        
        var_dump($_SESSION["user_guest_one"]);

        header("location: ../03_rsvp.php");
        $pdo = null;
        $statement = null;

        die();

    } catch (PDOExeption $e) {
        die("Query failed: " . $e->getMessage());
    }

} else {
    header("location: ../02_guest_login.php");
    die();
}

This file should correct identify whether the guest username exists via checks and it would then redirect them accordingly.