redis server connection error stacktrace

stacktrace.py

ConnectionError: Connection closed by server.
  File "redis/client.py", line 1788, in run
    pubsub.get_message(ignore_subscribe_messages=True, timeout=sleep_time)
  File "redis/client.py", line 1679, in get_message
    response = self.parse_response(block=(timeout is None), timeout=timeout)
  File "redis/client.py", line 1531, in parse_response
    response = self._execute(conn, try_read)
  File "redis/client.py", line 1507, in _execute
    return conn.retry.call_with_retry(
  File "redis/retry.py", line 49, in call_with_retry
    fail(error)
  File "redis/client.py", line 1509, in <lambda>
    lambda error: self._disconnect_raise_connect(conn, error),
  File "redis/client.py", line 1496, in _disconnect_raise_connect
    raise error
  File "redis/retry.py", line 46, in call_with_retry
    return do()
  File "redis/client.py", line 1508, in <lambda>
    lambda: command(*args, **kwargs),
  File "redis/client.py", line 1525, in try_read
    if not conn.can_read(timeout=timeout):
  File "redis/connection.py", line 854, in can_read
    return self._parser.can_read(timeout)
  File "redis/connection.py", line 341, in can_read
    return self._buffer and self._buffer.can_read(timeout)
  File "redis/connection.py", line 239, in can_read
    return bool(self.unread_bytes()) or self._read_from_socket(
  File "redis/connection.py", line 212, in _read_from_socket
    raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)