text: Title: DRF - Adding User from Panel vs adding with code error?
  Body: `class CustomerRegister(APIView):
      permission_classes = (permissions.AllowAny,)
  
      def post(self, request):
          data = request.data
          data['is_active'] = True
          serializer = UserSerializer(data=data)
          if serializer.is_valid():
              user = User.objects.create_user(**data)
              user.save()
              customer = Customer.objects.create(user=User.objects.get(username=data['username']))
              url, headers, body, status_code = self.create_token_response(request)
              return Response(json.loads(body), status=status_code)
  
          return Response(data=serializer.errors, status=status.HTTP_400_BAD_REQUEST)`
  
  When I am adding the user from the admin panel everything works and I am getting my tokens.
  
  When I use this code I am getting `{
      "error": "invalid_grant",
      "error_description": "Invalid credentials given."
  }`
  
  My request for the token is absolutely the same.
  Does anyone has any idea why? 
  