# Buggy code
def _run_current_session(self):
    try:
        if self.current_session is not None and self.current_session.is_active():
            self.logger.info(
                "Starting to receive messages from a new connection"
                f" (session id: {self.session_id()})"
            )
            self.current_session_state.terminated = False
            self.current_session.run_until_completion(self.current_session_state)
            self.logger.info(
                "Stopped receiving messages from a connection"
                f" (session id: {self.session_id()})"
            )
    except Exception as e:
        self.logger.exception(
            "Failed to start or stop the current session"
            f" (session id: {self.session_id()}, error: {e})"
        )


# Traceback (SlackApiError)
2021-02-14 18:19:49,579 ERROR    slack_sdk.rtm.v2          Failed to establish a connection (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81, error: _ssl.c:1108: The handshake operation timed out)
Traceback (most recent call last):
File "/opt/errbot/lib/python3.8/site-packages/slack_sdk/socket_mode/builtin/connection.py", line 109, in connect
sock.connect((hostname, port))
File "/usr/lib/python3.8/ssl.py", line 1342, in connect
self._real_connect(addr, False)
File "/usr/lib/python3.8/ssl.py", line 1333, in _real_connect
self.do_handshake()
File "/usr/lib/python3.8/ssl.py", line 1309, in do_handshake
self._sslobj.do_handshake()
socket.timeout: _ssl.c:1108: The handshake operation timed out
2021-02-14 18:19:49,579 INFO     slack_sdk.rtm.v2          The connection has been closed (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:19:49,579 INFO     slack_sdk.rtm.v2          The connection has been closed (session id: b88f63ee-d644-45a8-bf18-be36c8673728)
2021-02-14 18:19:49,579 INFO     slack_sdk.rtm.v2          A new session has been established (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:19:49,579 INFO     slack_sdk.rtm.v2          Connected to a new endpoint...
2021-02-14 18:19:59,590 DEBUG    slack_sdk.rtm.v2          This connection is already closed. (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:19:59,590 INFO     slack_sdk.rtm.v2          The session seems to be already closed. Going to reconnect... (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:19:59,590 INFO     slack_sdk.rtm.v2          Connecting to a new endpoint...
2021-02-14 18:20:00,075 ERROR    slack_sdk.rtm.v2          Failed to retrieve WSS URL: The request to the Slack API failed.
The server responded with: {'ok': False, 'error': 'ratelimited'}
2021-02-14 18:20:00,075 ERROR    slack_sdk.rtm.v2          Failed to check the current session or reconnect to the server (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81, error: SlackApiError, message: The request to the Slack API failed.
The server responded with: {'ok': False, 'error': 'ratelimited'})
2021-02-14 18:20:10,092 DEBUG    slack_sdk.rtm.v2          This connection is already closed. (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:20:10,117 INFO     slack_sdk.rtm.v2          The session seems to be already closed. Going to reconnect... (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:20:10,121 INFO     slack_sdk.rtm.v2          Connecting to a new endpoint...
2021-02-14 18:20:10,339 ERROR    slack_sdk.rtm.v2          Failed to retrieve WSS URL: The request to the Slack API failed.
The server responded with: {'ok': False, 'error': 'ratelimited'}
2021-02-14 18:20:10,339 ERROR    slack_sdk.rtm.v2          Failed to check the current session or reconnect to the server (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81, error: SlackApiError, message: The request to the Slack API failed.
The server responded with: {'ok': False, 'error': 'ratelimited'})
2021-02-14 18:20:20,350 DEBUG    slack_sdk.rtm.v2          This connection is already closed. (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:20:20,350 INFO     slack_sdk.rtm.v2          The session seems to be already closed. Going to reconnect... (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:20:20,350 INFO     slack_sdk.rtm.v2          Connecting to a new endpoint...
2021-02-14 18:20:20,556 ERROR    slack_sdk.rtm.v2          Failed to retrieve WSS URL: The request to the Slack API failed.
The server responded with: {'ok': False, 'error': 'ratelimited'}
2021-02-14 18:20:20,557 ERROR    slack_sdk.rtm.v2          Failed to check the current session or reconnect to the server (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81, error: SlackApiError, message: The request to the Slack API failed.
The server responded with: {'ok': False, 'error': 'ratelimited'})
2021-02-14 18:20:30,567 DEBUG    slack_sdk.rtm.v2          This connection is already closed. (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:20:30,567 INFO     slack_sdk.rtm.v2          The session seems to be already closed. Going to reconnect... (session id: 18e8f520-5e64-443c-98ed-089ab1ef6f81)
2021-02-14 18:20:30,567 INFO     slack_sdk.rtm.v2          Connecting to a new endpoint...

# Fixed code
def _run_current_session(self):
    if self.current_session is not None and self.current_session.is_active():
        session_id = self.session_id()
        try:
            self.logger.info(
                "Starting to receive messages from a new connection"
                f" (session id: {session_id})"
            )
            self.current_session_state.terminated = False
            self.current_session.run_until_completion(self.current_session_state)
            self.logger.info(
                "Stopped receiving messages from a connection"
                f" (session id: {session_id})"
            )
        except Exception as e:
            self.logger.exception(
                "Failed to start or stop the current session"
                f" (session id: {session_id}, error: {e})"
            )