Type object 'ModelTaskMetaState' has no attribute 'REJECTED'

[Moulde]

I have a weird issue after trying to reject a task. I am attempting to switch from redis to rabbitmq where the rejected / failed tasks should go to a specific queue where they can then be requeued manually if necessary.

But i get the following exception after trying to raise Reject(Exception("example"), requeue=False)

[2020-09-11 14:01:09,827: ERROR/ForkPoolWorker-1] Signal handler <function handle_task_postrun at 0x7f86adad2b50> raised: AttributeError("type object 'ModelTaskMetaState' has no attribute 'REJECTED'",)
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/celery/utils/dispatch/signal.py", line 288, in send
    response = receiver(signal=self, sender=sender, **named)
  File "/usr/local/lib/python2.7/site-packages/djcelery_model/models.py", line 234, in handle_task_postrun
    queryset.update(state=ModelTaskMetaState.lookup(state))
  File "/usr/local/lib/python2.7/site-packages/djcelery_model/models.py", line 33, in lookup
    return getattr(cls, state)
AttributeError: type object 'ModelTaskMetaState' has no attribute 'REJECTED'

Does anyone know what might be the issue? I am using the most recent version of celery 4.4.7

Does anyone have any ideas about why this causes an exception? It does seem like rejected is just not supported?

Best regards