JSON parse error in ajax script using Django Rest framework

I am using django rest framework.My views response is ok but when i submit my view using ajax it gives me an error json parse error.

Here is my views.py file:

@api_view(['GET', 'POST'])
@parser_classes([JSONParser])
def signup(request, format=None):
    if request.method == 'POST':
        data = JSONParser().parse(request)
        username = data.get('username')
        first_name = data.get('first_name')
        last_name = data.get('last_name')
        email = data.get('email')
        password = data.get('password')
        gender = data.get('gender')
        birth_date = data.get('birth_date')
        serializer = UserSerializer(data=data)
        if serializer.is_valid():
            user = User.objects.create_user(username=username,first_name=first_name,last_name=last_name,email=email,gender=gender,birth_date=birth_date)
            user.set_password(password)
            user.save()
            data = {'result': 'success', 'message':'You have registered successfully now you can login'}
            return Response(data=data, status=201)
        elif not serializer.is_valid():
            data = { 'result': 'error', 'message':serializer.errors}
            return Response(data=data)
    if not request.user.id and request.method == 'GET':
        return render(request, 'sessionauthapp/signup.html')

My ajax js script:

var frm = $('#signupform');
var token = '{{csrf_token}}';

$('#signupform').on('submit', function(e) {
    e.preventDefault();
    $.ajax({
        headers: { "X-CSRFToken": token },
        url: '/signup/',
        type: 'post',
        data: $(this).serialize(),
        dataType: "json",
        contentType: "application/json",

        success: function(data) {
            console.log(data);

          

        },
        error: function(data) {

        }
    });
    return false;
});

My ajax script gives me an error like json parse error but my views response is ok.