I don't receive notifications from Yandex.Checkout. What to do?

Question

Django

Good day.
I'm trying to receive notifications from Yandex checkout with this function:

def pay_status(request):
    subject, from_email, to = u'Название', 'почта@домен.ру', 'моя почта@mail.ru'
    html_content = 'Ok'
    text_content = ''
    msg = EmailMultiAlternatives(subject, text_content, from_email, [to])
    msg.attach_alternative(html_content, "text/html")
    msg.send()

    payment_id = request.data['object']['id']
    Payment.capture(payment_id)
    return HttpResponse(status=200)

After payment, according to the logic, I should receive a letter. But it doesn't come... When I enter the url manually, the letters come
I don't understand how to fix
Django==1.9