Celery not executing new tasks if redis lost connection is restablished

I have a Celery worker configured to connect to redis as follows:

 celery_app_site24x7 = Celery('monitoringExterne.celerys.site24x7',
                             broker=settings.REDIS['broker'], backend=settings.REDIS['backend'])

celery_app_site24x7.conf.broker_transport_options = {
    'visibility_timeout': 36000
}

celery_app_site24x7.conf.socket_timeout = 300
celery_app_site24x7.conf.broker_connection_max_retries = None
celery_app_site24x7.config_from_object('django.conf:settings')
celery_app_site24x7.autodiscover_tasks(lambda: settings.INSTALLED_APPS)

The issue is that if Redis is down and the connection is restablished new tasks added in the queue are not executed:

[2020-01-13 10:10:14,517: ERROR/MainProcess] consumer: Cannot connect to redis://xxx.xxx.xxx.xx:6380/10: Error while reading from socket: ('Connection closed by server.',).
Trying again in 2.00 seconds...

[2020-01-13 10:10:16,590: INFO/MainProcess] Connected to redis://xxx.xxx.xxx.xx:6380/10
[2020-01-13 10:10:16,699: INFO/MainProcess] mingle: searching for neighbors
[2020-01-13 10:10:17,766: INFO/MainProcess] mingle: all alone

I have manually called a celery task through the django shell as follows:

celery_tasks.site24x7.test.delay()

It returns me the Async task ID but the worker doesnot process this task.

<AsyncResult:ff634b85-edb5-44d4-bdb1-17a220761fcc>

If I continue to launch the task as delay the queue keeps incrementing:

127.0.0.1:6379[10]> llen site24x7
(integer) 4
127.0.0.1:6379[10]> llen site24x7
(integer) 5

Below are the output of the celery status and inspect

$ celery -A monitoringExterne –app=monitoringExterne.celerys.site24x7

status Error: No nodes replied within time constraint.

$ celery -A monitoringExterne –app=monitoringExterne.celerys.site24x7 inspect active

Error: No nodes replied within time constraint.