title: Rasa crashes when a message is sent
body: <p>I have installed Rasa without any errors. When I run rasa shell the server is started and I am presented with the chatbot prompt. when I enter hi I get the following error:</p>
  
  <pre><code>Bot loaded. Type a message and press enter (use '/stop' to exit):
  Your input -&gt;  hi
  Exception occurred while handling uri: 'http://localhost:5005/webhooks/rest/webhook?stream=true&amp;token='
  Traceback (most recent call last):
    File "g:\programs\python\python37\lib\site-packages\sanic\app.py", line 946, in handle_request
      request, request_name=name
  TypeError: _run_request_middleware() got an unexpected keyword argument 'request_name'
  Exception occurred in one of response middleware handlers
  Traceback (most recent call last):
    File "g:\programs\python\python37\lib\site-packages\sanic\app.py", line 1017, in handle_request
      request, response, request_name=name
  TypeError: _run_response_middleware() got an unexpected keyword argument 'request_name'
  2020-01-04 11:29:30 ERROR    asyncio  - Task exception was never retrieved
  future: &lt;Task finished coro=&lt;configure_app.&lt;locals&gt;.run_cmdline_io() done, defined at g:\programs\python\python37\lib\site-packages\rasa\core\run.py:124&gt; exception=ClientResponseError(RequestInfo(url=URL('http://localhost:5005/webhooks/rest/webhook?stream=true&amp;token='), method='POST', headers=&lt;CIMultiDictProxy('Host': 'localhost:5005', 'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'User-Agent': 'Python/3.7 aiohttp/3.6.2', 'Content-Length': '38', 'Content-Type': 'application/json')&gt;, real_url=URL('http://localhost:5005/webhooks/rest/webhook?stream=true&amp;token=')), (), status=500, message='Internal Server Error', headers=&lt;CIMultiDictProxy('Connection': 'keep-alive', 'Keep-Alive': '5', 'Content-Length': '144', 'Content-Type': 'text/html; charset=utf-8')&gt;)&gt;
  Traceback (most recent call last):
    File "g:\programs\python\python37\lib\site-packages\rasa\core\run.py", line 128, in run_cmdline_io
      server_url=constants.DEFAULT_SERVER_FORMAT.format("http", port)
    File "g:\programs\python\python37\lib\site-packages\rasa\core\channels\console.py", line 140, in record_messages
      async for response in bot_responses:
    File "g:\programs\python\python37\lib\site-packages\rasa\core\channels\console.py", line 104, in send_message_receive_stream
      async with session.post(url, json=payload, raise_for_status=True) as resp:
    File "g:\programs\python\python37\lib\site-packages\aiohttp\client.py", line 1012, in __aenter__
      self._resp = await self._coro
    File "g:\programs\python\python37\lib\site-packages\aiohttp\client.py", line 588, in _request
      resp.raise_for_status()
    File "g:\programs\python\python37\lib\site-packages\aiohttp\client_reqrep.py", line 946, in raise_for_status
      headers=self.headers)
  aiohttp.client_exceptions.ClientResponseError: 500, message='Internal Server Error', url=URL('http://localhost:5005/webhooks/rest/webhook?stream=true&amp;token=')
  
  </code></pre>
  
  <p>I have had no issues installing an since I am new to Rasa I am not sure what the problem is.</p>
  
  <p>Please advise.
  Thanks</p>