Celery tasks are not running

I'm working on a drf app where I need to use celery. I'm trying to run a simple task to make sure the set up is solid for later.

settings.py:

CELERY_BROKER_URL = 'redis://localhost:6379/0'
CELERY_ACCEPT_CONTENT = ['json']
CELERY_TASK_SERIALIZER = 'json'

tasks.py:

@shared_task
def add(x, y):
    print(f"Running add({x}, {y})")
    return x + y

I've opened 3 tabs and running these 3 in each:

1. python3 manage.py runserver
2. redis-server
3. celery -A sauftrag_social worker --loglevel=info

All of them are ran successfully and I see the add task in [tasks] part in the celery worker tab.

I'm calling the task like this: result = add.delay(2, 3)

After running about 10 minutes it's returning this error message:

kombu.exceptions.OperationalError: Timeout connecting to server