Unable to make thumbnails due to doctor unavailability

[sentry-io]

Sentry Issue: BIGCASES2-29

ConnectionError: HTTPConnectionPool(host='cl-doctor', port=5050): Max retries exceeded with url: /convert/pdf/thum...

ConnectionRefusedError: [Errno 111] Connection refused
  File "urllib3/connection.py", line 174, in _new_conn
    conn = connection.create_connection(
  File "urllib3/util/connection.py", line 95, in create_connection
    raise err
  File "urllib3/util/connection.py", line 85, in create_connection
    sock.connect(sa)

NewConnectionError: <urllib3.connection.HTTPConnection object at 0x7f2e1ec1d390>: Failed to establish a new connection: [Errno 111] Connection refused
(5 additional frame(s) were not displayed)
...
  File "http/client.py", line 1281, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "http/client.py", line 1041, in _send_output
    self.send(msg)
  File "http/client.py", line 979, in send
    self.connect()
  File "urllib3/connection.py", line 205, in connect
    conn = self._new_conn()
  File "urllib3/connection.py", line 186, in _new_conn
    raise NewConnectionError(

MaxRetryError: HTTPConnectionPool(host='cl-doctor', port=5050): Max retries exceeded with url: /convert/pdf/thumbnails/ (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f2e1ec1d390>: Failed to establish a new connection: [Errno 111] Connection refused'))
  File "requests/adapters.py", line 486, in send
    resp = conn.urlopen(
  File "urllib3/connectionpool.py", line 787, in urlopen
    retries = retries.increment(
  File "urllib3/util/retry.py", line 592, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))

ConnectionError: HTTPConnectionPool(host='cl-doctor', port=5050): Max retries exceeded with url: /convert/pdf/thumbnails/ (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f2e1ec1d390>: Failed to establish a new connection: [Errno 111] Connection refused'))
(6 additional frame(s) were not displayed)
...
  File "bc/subscription/tasks.py", line 373, in make_post_for_webhook_event
    files = get_thumbnails_from_range(document, thumbnail_range)
  File "bc/core/utils/microservices.py", line 20, in get_thumbnails_from_range
    thumbnails = requests.post(