Exception 504 when registering the consumer - symfony

Question

I've been working with Symfony 2.7 and the RabbitMQBundle to handle some long processes asynchronously.
After facing the issue where the MySQL connection dies after a few minutes, I discovered rabbitmq-cli-consumer, a small app in Go that takes care of consuming the queue, and gives its content to a command.
In my case, I use it with this command: ./rabbitmq-cli-consumer -c configuration-stock.conf --include -V -e 'php app/console amqp:consume:stock --env=prod -vvv', with this configuration file:
[rabbitmq]
host = HOST
username = USERNAME
password = PASSWORD
vhost=/VHOST
port=PORT
queue=stock
compression=Off
[exchange]
name=exports
type=direct
durable=On
[queuesettings]
routingkey=stock
messagettl=10000
deadLetterExchange=exports.dl
deadLetterroutingkey=stock
priority=10
To handle errors, I intend to use RabbitMQ's x-dead-letter-exchange and x-dead-letter-routing-key configuration, to be able to retry the message later (in case something went temporarly wrong).
My issue is that, when I define my queues in RabbitMQBundle's configuration, rabbitmq-cli-consumer is unable to consume the queue, throwing this error:
2018/04/23 11:35:54 Connecting RabbitMQ...
2018/04/23 11:35:54 Connected.
2018/04/23 11:35:54 Opening channel...
2018/04/23 11:35:54 Done.
2018/04/23 11:35:54 Setting QoS...
2018/04/23 11:35:54 Succeeded setting QoS.
2018/04/23 11:35:54 Declaring queue "stock"...
2018/04/23 11:35:54 Registering consumer...
2018/04/23 11:35:54 failed to register a consumer: Exception (504) Reason: "channel/connection is not open"
Here is the configuration I use for RabbitMQBundle:
old_sound_rabbit_mq:
producers:
exports:
connection: default
exchange_options:
name: 'exports'
type: direct
exports_dl:
connection: default
exchange_options:
name: 'exports.dl'
type: direct
consumers:
stock_dead_letter:
connection: default
exchange_options:
name: exports.dl
type: direct
queue_options:
name: stock.dl
routing_keys:
- stock
arguments:
x-dead-letter-exchange: ['S', 'exports']
x-dead-letter-routing-key: ['S', 'stock']
x-message-ttl: ['I', 60000]
callback: amqp.consumers.exports.stock
multiple_consumers:
exports:
connection: default
exchange_options:
name: 'exports'
type: direct
queues:
stock:
name: stock
callback: amqp.consumers.exports.stock
routing_keys:
- stock
arguments:
x-dead-letter-exchange: ['S', 'exports.dl']
x-dead-letter-routing-key: ['S', 'stock']
Has anyone ever encountered something similar ? And how did you solve it ?