Waze_travel_time error

i have error with waze_travel_time

Error doing job: Future exception was never retrieved
Traceback (most recent call last):
  File "/usr/lib/python3.5/concurrent/futures/thread.py", line 55, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/sensor/waze_travel_time.py", line 74, in <lambda>
    EVENT_HOMEASSISTANT_START, lambda _: sensor.update())
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/sensor/waze_travel_time.py", line 204, in update
    routes = params.calc_all_routes_info(real_time=self._realtime)
  File "/srv/homeassistant/lib/python3.5/site-packages/WazeRouteCalculator/WazeRouteCalculator.py", line 145, in calc_all_routes_info
    routes = self.get_route(npaths, time_delta)
  File "/srv/homeassistant/lib/python3.5/site-packages/WazeRouteCalculator/WazeRouteCalculator.py", line 95, in get_route
    response_json = response.json()
  File "/srv/homeassistant/lib/python3.5/site-packages/requests/models.py", line 897, in json
    return complexjson.loads(self.text, **kwargs)
  File "/usr/lib/python3.5/json/__init__.py", line 319, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.5/json/decoder.py", line 339, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.5/json/decoder.py", line 357, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

I have the same error for quite some time now. Not sure what it may cause.