MWAA & SlackWebHookOperator - SSLError: EOF occurred in violation of protocol - ssl

Question

Background
One use case I have with MWAA is sending out Slack notifications by the use of Slack Incoming Webhook. To do so, I have installed the Slack Provider package so that I could create a connector and make use of the operator called SlackWebhookOperator.
To validate the connection and test the operator, I’ve created a simple DAG to send out a message to a slack channel:
from airflow import DAG
from airflow.contrib.operators.slack_webhook_operator import SlackWebhookOperator
with DAG(
'slack_operator_validation',
default_args={
'depends_on_past': True,
'email': \['XXX#XXX.com'\],
'email_on_failure': True,
'email_on_retry': False,
'retries': 7,
'retry_delay': timedelta(minutes=1)
},
description='Send slack notification using SlackWebhookOperator',
schedule_interval= None,
start_date=datetime(2021, 1, 1),
catchup=False,
tags=\['POC','SNOW-ALERT'\]
) as dag:
slack_msg = "Testing SlackWebhookOperator from TEST MWAA"
slack_test = SlackWebhookOperator(
task_id='slack_test',
http_conn_id='slack_connector',
webhook_token='/XXXX/XXXX/XXXX',
message=slack_msg,
channel='#test-airflow-snow-alerts',
username='Airflow TEST MWAA',
icon_emoji=None,
link_names=False,
dag=dag)
slack_test
Issue description
When executing the DAG slack_operator_validation, the task 'slack_test' fails with the following error:
[2023-01-19, 02:07:39 UTC] {{client.py:216}} ERROR - Failed to send a request to Slack API server: <urlopen error EOF occurred in violation of protocol (_ssl.c:1091)>
After some investigation I found this thread where a couple of folks have resolved the issue by installing ndg-httpsclient & pyasn1 libs. With that in mind I applied a terraform change to install these packages into MWAA environment and it succeeded. However it didn’t fix the issue.