Celery schedule doesn't trigger the tasks, no error reported - django

Question

I'm using Django with celery:
In celery.py I have:
app.conf.beat_schedule = {
'send_notes_email': {
'task': 'send_notes_email_async',
'schedule': crontab(minute=3),
},
}
The task is set:
#app.task(bind=True, name='send_notes_email_async', max_retries=3)
def send_notes_email_async():
print('a')
send_notes_email()
Celery is working, recognize the tasks, but doesn't trigger after 3 minutes.
Also no errors.
Redis reports keys
Celery tasks are working without schedule
-------------- celery#WIN-U5VDSO5V1CK v4.2.1 (windowlicker)
---- **** -----
--- * *** * -- Windows-7-6.1.7601-SP1
-- * - **** ---
- ** ---------- [config]
- ** ---------- .> app: PH:0x3d2d128
- ** ---------- .> transport: redis://localhost:6379//
- ** ---------- .> results: redis://localhost:6379/
- *** --- * --- .> concurrency: 2 (eventlet)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** -----
-------------- [queues]
.> celery exchange=celery(direct) key=celery
[tasks]
. send_notes_email_async

Answer 1

Your beat schedule configuration is wrong, minute=3 in cronjob means that execute the task at minute 3 (01:03, 02:03, 03:03, 04:03...).
This is what you want, which executes the task every 3 minutes:
app.conf.beat_schedule = {
'send_notes_email': {
'task': 'send_notes_email_async',
'schedule': crontab(minute=*/3),
},
}