Login with token django-rest-framework

I am working on a project with the django rest framework. I created the registration view without any problem, but in the login view I have an issue: when I try to log in, the response returns "Invalid credentials"

view.py:

class ObtainAuthTokenView(APIView):
    authentication_classes = []
    permission_classes = []

    def post(self, request):
        context = {}

        email = request.POST.get('username')
        password = request.POST.get('password')
        account = authenticate(email=email, password=password)
        if account:
            try:
                token = Token.objects.get(user=account)
            except Token.DoesNotExist:
                token = Token.objects.create(user=account)
            context['response'] = 'Successfully authenticated.'
            context['pk'] = account.pk
            context['email'] = email.lower()
            context['token'] = token.key
        else:
            context['response'] = 'Error'
            context['error_message'] = 'Invalid credentials'

        return Response(context)

urls.py

urlpatterns = [
    path('login', ObtainAuthTokenView.as_view(), name="login"),
]

I used this data to post:

{"username":"[email protected]","password":"123456"}

After I post this data the response returns 'invalid credentials'. I found out that maybe the email and password after get the request are equal nun.

so why am I facing this issue?