Celery send_task doesn't send tasks

I have a server running Celery with RabbitMQ. But when I try to send tasks using send_task, it just returns with an AsyncResult object. But the actual task is not running (even though the workers and the queues are empty) ``` c = Celery("tasks", broker="amqp://guest@127.0.0.1//") c.send_task("tasks.printing.test_print", (100), queue="print_queue", routing_key="printing.test_print") ``` My celery configuration is: ``` CELERY_QUEUES = ( Queue('default', routing_key='task.#'), Queue('print_queue', routing_key='printing.#'), ) CELERY_DEFAULT_EXCHANGE = 'tasks' CELERY_ROUTES = { 'tasks.printing.test_print': { 'queue': 'print_queue', 'routing_key': 'printing.test_print', }} BROKER_URL = 'amqp://' ``` I execute only one worker: ``` celery -A celerymain worker --loglevel=debug ``` This is it's initial log: ``` - ** ---------- [config] - ** ---------- .> app: __main__:0x7eff96903b50 - ** ---------- .> transport: amqp://guest:**@localhost:5672// - ** ---------- .> results: amqp:// - *** --- * --- .> concurrency: 4 (prefork) -- ******* ---- --- ***** ----- [queues] -------------- .> default exchange=tasks(topic) key=task.# .> print_queue exchange=tasks(topic) key=printing.# [tasks] . test_print ``` This is the task: ``` class test_print(Task): name = "test_print" def run(self,a): log.info("running") print a ``` The rabbitMQ queue 'print_queue' stays empty and there is nothing new in the rabbitMQ logs. I have 4 GB free space so it's not a disk space problem. What can be the problem here?