How to pinpoint fault component

Configuration
1

Recently (since 43 i guess) started seeing the following error in logs. Wonder which component is causin it? How to pin point it?

2017-05-15 14:56:15 ERROR (MainThread) [homeassistant.core] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/lib/python3.4/asyncio/tasks.py", line 233, in _step
    result = coro.throw(exc)
  File "/srv/homeassistant/homeassistant_venv/lib/python3.4/site-packages/homeassistant/components/websocket_api.py", line 363, in forward_events
    yield from self.send_message(event_message(msg['id'], event))
  File "/home/homeassistant/.homeassistant/deps/aiohttp/http_writer.py", line 127, in drain
    yield from self._protocol._drain_helper()
  File "/usr/lib/python3.4/asyncio/streams.py", line 197, in _drain_helper
    yield from waiter
  File "/usr/lib/python3.4/asyncio/futures.py", line 388, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.4/asyncio/tasks.py", line 286, in _wakeup
    value = future.result()
  File "/usr/lib/python3.4/asyncio/futures.py", line 277, in result
    raise self._exception
  File "/usr/lib/python3.4/asyncio/selector_events.py", line 582, in _read_ready
    data = self._sock.recv(self.max_size)
OSError: [Errno 113] No route to host
2

I also had this kind of errors (Automations not working anymore). In my case it was a faulty automation. So I would suggest to look into this area first.