Django stripe and stripe webhook error : {"error": "Missing stripe signature"}

Question

please, I need your help. I'm trying to set up a striped payment system in the django app. However, I can't seem to connect the webhook to my logic. In addition, the handle_checkout_session function which should send a message after the success of each payment does not send any message. However, when I make a payment it works fine. But, Webhook and handle_checkout_session doesn't work. Your help will be welcome... Here is my code.

def stripe_config(request):
    if request.method == 'GET':
        stripe_config = {'publicKey': settings.STRIPE_PUBLIC_KEY}
        return JsonResponse(stripe_config, safe=False)

login_required(login_url="login")
def stripe_payment(request):
    if request.method == 'GET':
        domain_url = getattr(settings, 'DOMAIN_URL')
        success_url = domain_url + reverse('stripe_success') + '?session_id={CHECKOUT_SESSION_ID}'
        cancel_url = domain_url + reverse('stripe_cancel')
        stripe.api_key = settings.STRIPE_SECRET_KEY
        order_id = request.GET.get('order_id')

        try:
            order = Order.objects.get(user=request.user, is_ordered=False, order_number=order_id)
            checkout_session = stripe.checkout.Session.create(
                client_reference_id=request.user.id if request.user.is_authenticated else None,
                success_url=success_url,
                cancel_url=cancel_url,
                payment_method_types=['card'],
                mode='payment',
                line_items=[
                    {
                        'price_data': {
                            'currency': 'eur',
                            'unit_amount': int(order.order_total * 100),
                            'product_data': {
                                'name': "Buy now",
                            },
                        },
                        'quantity': 1,
                    }
                ]
            )

            return JsonResponse({
                'sessionId': checkout_session['id']
            })
        except Order.DoesNotExist:
            return JsonResponse({
                'error': 'Order does not exist or has already been processed.'
            }, status=404)
        except stripe.error.StripeError as e:
            return JsonResponse({
                'error': str(e)
            }, status=500)

    return JsonResponse({'error': 'Invalid request method.'}, status=400)

@csrf_exempt
def stripe_webhook(request):
    stripe.api_key = settings.STRIPE_SECRET_KEY
    endpoint_secret = settings.STRIPE_WEBHOOK_SECRET

    payload = request.body
    sig_header = request.META.get('HTTP_STRIPE_SIGNATURE')
    print(sig_header)

    if sig_header is None:
        return JsonResponse({'error': 'Missing stripe signature'}, status=400)

    try:
        event = stripe.Webhook.construct_event(
            payload, sig_header, endpoint_secret
        )
    except ValueError as e:
        return JsonResponse({'error': str(e)}, status=400)
    except stripe.error.SignatureVerificationError as e:
        return JsonResponse({'error': str(e)}, status=400)

    if event['type'] == 'checkout.session.completed':
        session = event['data']['object']
        handle_checkout_session(session)

    return JsonResponse({'status': 'success'}, status=200)

def handle_checkout_session(session):
    try:
        order = Order.objects.get(payment__payment_id=session['id'])
        order.is_ordered = True
        order.save()

        ordered_products = OrderProduct.objects.filter(order_id=order.id)
        subtotal = 0
        tax = 0
        taxdhl = 0
        grand_total = 0
        grand_total_dhl = 0

        for i in ordered_products:
            subtotal += i.product_price * i.quantity
            tax += (2*subtotal)/100
            taxdhl = 1
            grand_total += subtotal + tax
            grand_total_dhl += grand_total + taxdhl

        user = order.user
        current_site = get_current_site(None)
        mail_subject = 'Thank you for your order!'
        message = render_to_string('orders/order_received_email.html', {
            'user': user,
            'order': order,
            'grand_total': grand_total,
            'grand_total_dhl': grand_total_dhl,
            'ordered_products': ordered_products,
            'tax': tax, 
            'taxdhl': taxdhl,
            'domain': current_site.domain,
            'uid': urlsafe_base64_encode(force_bytes(user.pk)),
            'token': default_token_generator.make_token(user),
        })

        from_email = 'Parisianist <customercare@parisianist.fr>'
        to_email = user.email

        mail = Mail(
            from_email=Email(from_email),
            to_emails=to_email,
            subject=mail_subject,
            html_content=message
        )

        try:
            sg = sendgrid.SendGridAPIClient(api_key=settings.SENDGRID_API_KEY)
            response = sg.send(mail)
            print(f"SendGrid Response Status Code: {response.status_code}")
            print(f"SendGrid Response Body: {response.body.decode('utf-8') if response.body else 'No Body'}")
            print(f"SendGrid Response Headers: {response.headers}")
        except Exception as e:
            print(f"An error occurred while sending email: {e}")

    except Order.DoesNotExist:
        pass

I would really like to know what the problem is and how to correct it.