405 method not allowed PHP

Пишу простой проект на PHP. У меня есть простая форма регистрации и скрипт, который должен добавлять данные в БД. Но каждый раз при нажатии на кнопку submit выдается ошибка 405 method not allowed. Сам html код

<form action="php/save_user.php" method="post">
                    <div class="form-group">
                        <label for="nameInput">Name: </label>
                        <input type="text" class="form-control" id="nameInput" name="name" placeholder="Name">
                    </div>

                    <div class="form-group">
                        <label for="surnameInput">Surname: </label>
                        <input type="text" class="form-control" id="surnameInput" name="surname" placeholder="Name">
                    </div>

                    <div class="form-group">
                        <label for="usernameInput">Username: </label>
                        <input type="text" class="form-control" id="usernameInput" name="username" placeholder="Name">
                    </div>

                    <div class="form-group">
                        <label for="emailInput">Email: </label>
                        <input type="email" class="form-control" id="emailInput" name="email" placeholder="Name">
                    </div>

                    <div class="form-group">
                        <label for="passwordInput">Password: </label>
                        <input type="password" class="form-control" id="password" name="password" placeholder="Name">
                    </div>

                    <input type="submit" class="btn btn-confirm" value="Register">
                </form>

А также php код

    <?php
    if(isset($_POST['name'])) {
        $name = $_POST['name'];
    }
    if($name == '') {
        unset($name);
    }

    if(isset($_POST['surname'])) {
        $surname = $_POST['surname'];
    }
    if($surname == '') {
        unset($surname);
    }

    if(isset($_POST['username'])) {
        $username = $_POST['username'];
    }
    if($username == '') {
        unset($username);
    }

    if(isset($_POST['email'])) {
        $email = $_POST['email'];
    }
    if($email == '') {
        unset($email);
    }

    if(isset($_POST['password'])) {
        $password = $_POST['password'];
    }
    if($password == '') {
        unset($password);
    }

    if(empty($name) || empty($surname) || empty($username) || empty($email) || empty($password)) {
        exit("You don't write all information. Please try again");
    }

    $name = stripslashes($name);
    $name = htmlspecialchars($name);

    $surname = stripslashes($surname);
    $surname = htmlspecialchars($surname);

    $usernmae = stripslashes($username);
    $username = htmlspecialchars($username);

    $email = stripslashes($email);
    $email = htmlspecialchars($email);

    $password = stripslashes($password);
    $password = htmlspecialchars($password);

    $name = trim($name);
    $surname = trim($surname);
    $username = trim($username);
    $email = trim($email);
    $password = trim($password);

    // echo $name;
    // echo $surname;
    // echo $username;
    // echo $email;
    // echo $password;

    // include("db.php");

    // $result = mysql_query("SELECT Id FROM users WHERE users.login = '$login', $db");
    // $myrow = mysql_fetch_array($result);
    // if(!empty($myrow['id'])) {
    //  exit("This user already exist");
    // }

    // $command = mysql_query("INSERT INTO users (Name, Surname, Username, Email, Password) VALUES ('$name', '$surname', '$username', '$email', '$password');");
    // if($command == 'TRUE') {
    //  echo "You are succesfully registered!";
    // }
    // else {
    //  echo "Error! You are not registered!";
    // }
?> 

Часть кода я закомментировал, так как думал, что ошибка в нем. Как оказалось, нет. Буду благодарен за любую помощь