django rest authentication return "don't include authentication information"

Question

I am making django authentication function via rest framework. I made view.py, serizlizers.py and backends.py. And I setup settings.py to call my own authentication function. But something is wrong and I got the error message that means "detail" : "don't include authentication information".

I have no idea what is wrong of my function. Please give me an advice.

backends.py
class RemoshinUserAuthBackend(BaseAuthentication):
 def authenticate(self, username=None, password=None):
 try:
 user = RemoshinUser.objects.get(username=username)
 if not user.check_password(password):
 return None
 except RemoshinUser.DoesNotExist:
 return None
 return user
 def get_user(self, user_id):
 try:
 return User.objects.get(pk=user_id)
 except User.DoesNotExist:
 return None
views.py
@method_decorator(csrf_exempt, name='dispatch')
class UserAuthenticationView(APIView):
 authentication_classes = (RemoshinUserAuthBackend, BasicAuthentication)
 permission_classes = (IsAuthenticated,)
 serializer_class = RemoshinUserAuthInputSerializer
 def get(self, request, format=None):
 content = {
 'user': request.user.username,
 'auth': None,
 }
 return Response(content)
 def post(self, request):
 serializer = RemoshinUserAuthInputSerializer(data=request.data)
 serializer.is_valid(raise_exception=True)
 user = authenticate(**serializer.data)
 if not user:
 raise AuthenticationFailed()
 return Response(serializer.data)
serializers.py
class RemoshinUserAuthInputSerializer(serializers.ModelSerializer):
 class Meta:
 model = RemoshinUser
 fields = ('username', 'password')