Problem with rasa slack integration

Hi,

I have rasa setup with training data and custom actions and it works fine. I am now trying to connect to slack which is not working specially when response contains text with buttons. Here are some details -

Rasa Version : 1.8.0 I have followed the process as mentioned here here .

here is my code which is running the server

from rasa.core.agent import Agent
from rasa.core.channels.slack import SlackInput
from rasa.core.interpreter import RasaNLUInterpreter
from rasa.utils.endpoints import EndpointConfig

import logging
logging.basicConfig(level="DEBUG")

action_endpoint = EndpointConfig(url="http://localhost:5055/webhook")
interp = RasaNLUInterpreter("./models/nlu/")
agent = Agent.load(
    model_path="./models",
    interpreter=interp,
   action_endpoint=action_endpoint
)

in_channel = SlackInput('xoxb-XXXXXXXXXXXXXXXXXXX', slack_retry_reason_header="x-slack-retry-reason", slack_retry_number_header="x-slack-retry-num")
agent.handle_channels([in_channel], 5005)

here is the error I am getting

ERROR:rasa.core.processor:Encountered an exception while running action 'form_getelementdetailsmttr'. Bot will continue, but the actions events are lost. Please check the logs of your action server for more information.
DEBUG:rasa.core.processor:
Traceback (most recent call last):
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\rasa\core\processor.py", line 596, in _run_action
    events = await action.run(output_channel, nlg, tracker, self.domain)
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\rasa\core\actions\action.py", line 549, in run
    json=json_body, method="post", timeout=DEFAULT_REQUEST_TIMEOUT
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\rasa\utils\endpoints.py", line 146, in request
    **kwargs,
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\aiohttp\client.py", line 1012, in __aenter__
    self._resp = await self._coro
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\aiohttp\client.py", line 483, in _request
    timeout=real_timeout
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\aiohttp\connector.py", line 523, in connect
    proto = await self._create_connection(req, traces, timeout)
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\aiohttp\connector.py", line 859, in _create_connection
    req, traces, timeout)
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\aiohttp\connector.py", line 986, in _create_direct_connection
    req=req, client_error=client_error)
  File "c:\python\Lib\asyncio\coroutines.py", line 129, in throw
    return self.gen.throw(type, value, traceback)
  File "D:\_PythonProjects_\RnD\rasa_latest\venv\lib\site-packages\aiohttp\connector.py", line 936, in _wrap_create_connection
    return await self._loop.create_connection(*args, **kwargs)  # type: ignore  # noqa
  File "c:\python\Lib\asyncio\base_events.py", line 781, in create_connection
    yield from self.sock_connect(sock, address)
  File "c:\python\Lib\asyncio\selector_events.py", line 439, in sock_connect
    return (yield from fut)
concurrent.futures._base.CancelledError
DEBUG:rasa.core.processor:Action 'form_getelementdetailsmttr' ended with events '[]'.

I am seeing this error when response from bot it just text but in that case response is reaching to slack. I am running action server into another window.

Thanks Neeraj