I'm trying to place an order, but I constantly encounter errors of a different nature (now DoesNotExist at /make-order/), I don't understand what's wrong?

Question

Django

The code

#models.py
User = get_user_model()
class Category(models.Model):
    name = models.CharField(max_length=250, unique=True)
    slug = models.SlugField(max_length=250, unique=True)
    description = models.TextField(blank=True)
    image = models.ImageField(upload_to='category', blank=True)

    class Meta:
        ordering = ('name',)
        verbose_name = 'category'
        verbose_name_plural = 'categories'

    def get_url(self):
        return reverse('products_by_category', args=[self.slug])

    def __str__(self):
        return self.name


class Product(models.Model):
    name = models.CharField(max_length=250, unique=True)
    slug = models.SlugField(max_length=250, unique=True)
    description = models.TextField(blank=True)
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    image = models.ImageField(upload_to='product', blank=True)
    stock = models.IntegerField()
    available = models.BooleanField(default=True)
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ('name',)
        verbose_name = 'product'
        verbose_name_plural = 'products'

    def get_url(self):
        return reverse('product_detail', args=[self.category.slug, self.slug])

    def __str__(self):
        return self.name


class Cart(models.Model):
    cart_id = models.CharField(max_length=250, blank=True)
    date_added = models.DateField(auto_now_add=True)

    class Meta:
        ordering = ['date_added']
        db_table = 'Cart'

    def __str__(self):
        return self.cart_id


class CartItem(models.Model):
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    cart = models.ForeignKey(Cart, on_delete=models.CASCADE)
    quantity = models.IntegerField()
    active = models.BooleanField(default=True)

    class Meta:
        db_table = 'CartItem'

    def sub_total(self):
        return self.product.price * self.quantity

    def __str__(self):
        return self.product


class Customer(models.Model):
    user = models.ForeignKey(User, verbose_name='Пользователь', on_delete=models.CASCADE)
    phone = models.CharField(max_length=20, verbose_name='Номер телефона', null=True, blank=True)
    address = models.CharField(max_length=255, verbose_name='Адрес', null=True, blank=True)
    orders = models.ManyToManyField('Order', verbose_name='Заказы покупателя', related_name='related_order')

    def __str__(self):
        return "Покупатель: {} {}".format(self.user.first_name, self.user.last_name)


class Order(models.Model):
    STATUS_NEW = 'new'
    STATUS_IN_PROGRESS = 'in_progress'
    STATUS_READY = 'is_ready'
    STATUS_COMPLETED = 'completed'

    BUYING_TYPE_SELF = 'self'
    BUYING_TYPE_DELIVERY = 'delivery'

    STATUS_CHOICES = (
        (STATUS_NEW, 'Новый заказ'),
        (STATUS_IN_PROGRESS, 'Заказ в обработке'),
        (STATUS_READY, 'Заказ готов'),
        (STATUS_COMPLETED, 'Заказ выполнен')
    )

    BUYING_TYPE_CHOICES = (
        (BUYING_TYPE_SELF, 'Самовывоз'),
        (BUYING_TYPE_DELIVERY, 'Доставка')
    )

    customer = models.ForeignKey(Customer, verbose_name='Покупатель', related_name='related_orders',
                                 on_delete=models.CASCADE)
    first_name = models.CharField(max_length=255, verbose_name='Имя')
    last_name = models.CharField(max_length=255, verbose_name='Фамилия')
    phone = models.CharField(max_length=20, verbose_name='Телефон')
    cart = models.ForeignKey(Cart, verbose_name='Корзина', on_delete=models.CASCADE, null=True, blank=True)
    address = models.CharField(max_length=1024, verbose_name='Адрес', null=True, blank=True)
    status = models.CharField(
        max_length=100,
        verbose_name='Статус заказ',
        choices=STATUS_CHOICES,
        default=STATUS_NEW
    )
    buying_type = models.CharField(
        max_length=100,
        verbose_name='Тип заказа',
        choices=BUYING_TYPE_CHOICES,
        default=BUYING_TYPE_SELF
    )
    comment = models.TextField(verbose_name='Комментарий к заказу', null=True, blank=True)
    created_at = models.DateTimeField(auto_now=True, verbose_name='Дата создания заказа')
    order_date = models.DateField(verbose_name='Дата получения заказа', default=timezone.now)

    def __str__(self):
        return str(self.id)
#view.py



def home(request, category_slug=None):
    category_page = None
    products = None
    if category_slug != None:
        category_page = get_object_or_404(Category, slug=category_slug)
        products = Product.objects.filter(category=category_page, available=True)
    else:
        products = Product.objects.all().filter(available=True)
    return render(request, 'home.html', {'category': category_page, 'products': products})


def product(request, category_slug, product_slug):
    try:
        product = Product.objects.get(category__slug=category_slug, slug=product_slug)
    except Exception as e:
        raise e
    return render(request, 'product.html', {'product': product})


def _cart_id(request):
    cart = request.session.session_key
    if not cart:
        cart = request.session.create()
    return cart


def add_cart(request, product_id):
    product = Product.objects.get(id=product_id)
    try:
        cart = Cart.objects.get(cart_id=_cart_id(request))
    except Cart.DoesNotExist:
        cart = Cart.objects.create(cart_id=_cart_id(request))
        cart.save()
    try:
        cart_item = CartItem.objects.get(product=product, cart=cart)
        if cart_item.quantity < cart_item.product.stock:
            cart_item.quantity += 1
        cart_item.save()
    except CartItem.DoesNotExist:
        cart_item = CartItem.objects.create(product=product, quantity=1, cart=cart)
        cart_item.save()

    return redirect('cart_detail')


def cart_detail(request, total=0, counter=0, cart_items=None):
    try:
        cart = Cart.objects.get(cart_id=_cart_id(request))
        cart_items = CartItem.objects.filter(cart=cart, active=True)
        for cart_item in cart_items:
            total += (cart_item.product.price * cart_item.quantity)
            counter += cart_item.quantity

    except ObjectDoesNotExist:
        pass

    return render(request, 'cart.html', dict(cart_items=cart_items, total=total, counter=counter))


def cart_remove(request, product_id):
    cart = Cart.objects.get(cart_id=_cart_id(request))
    product = get_object_or_404(Product, id=product_id)
    cart_item = CartItem.objects.get(product=product, cart=cart)
    if cart_item.quantity > 1:
        cart_item.quantity -= 1
        cart_item.save()
    else:
        cart_item.delete()
    return redirect('cart_detail')


def cart_remove_product(request, product_id):
    cart = Cart.objects.get(cart_id=_cart_id(request))
    product = get_object_or_404(Product, id=product_id)
    cart_item = CartItem.objects.get(product=product, cart=cart)
    cart_item.delete()
    return redirect('cart_detail')


def signUpView(request):
    if request.method == 'POST':
        form = SignUpForm(request.POST)
        if form.is_valid():
            form.save()
            username = form.cleaned_data.get('username')
            signup_user = User.objects.get(username=username)
            user_group = Group.objects.get(name='User')
            user_group.user_set.add(signup_user)
    else:
        form = SignUpForm()
    return render(request, 'signup.html', {'form': form})


def loginView(request):
    if request.method == 'POST':
        form = AuthenticationForm(data=request.POST)
        if form.is_valid():
            username = request.POST['username']
            password = request.POST['password']
            user = authenticate(username=username, password=password)
            if user is not None:
                login(request, user)
                return redirect('home')
            else:
                return redirect('signup')

    else:
        form = AuthenticationForm()
    return render(request, 'login.html', {'form': form})


def signoutView(request):
    logout(request)
    return redirect('login')


class MakeOrderView(View):

    @transaction.atomic
    def post(self, request, *args, **kwargs):
        form = OrderForm(request.POST or None)
        customer = Customer.objects.get(user=request.user)
        print(customer)
        if form.is_valid():
            new_order = form.save(commit=False)
            new_order.customer = customer
            new_order.first_name = form.cleaned_data['first_name']
            new_order.last_name = form.cleaned_data['last_name']
            new_order.phone = form.cleaned_data['phone']
            new_order.address = form.cleaned_data['address']
            new_order.buying_type = form.cleaned_data['buying_type']
            new_order.order_date = form.cleaned_data['order_date']
            new_order.comment = form.cleaned_data['comment']
            new_order.save()
            new_order.cart = cart_detail
            new_order.save()
            customer.orders.add(new_order)
            messages.add_message(request, messages.INFO, 'Спасибо за заказ! Менеджер с Вами свяжется')
            return HttpResponseRedirect('/')
        return HttpResponseRedirect('/checkout/')


class CheckoutView(View):

    def get(self, request, *args, **kwargs):
        categories = Category.objects.all()
        form = OrderForm(request.POST or None)
        context = {
            'cart': cart_detail,
            'categories': categories,
            'form': form
        }
        return render(request, 'checkout.html', context)