Unexpected PRECONDITION_FAILED

I must be doing something wrong.

Using AWS’s hosted RabbitMQ, I am processing simple messages and manually acking them using noAck: false for the queue and channel.ack(msg) to acknowledge them. However, after 30 minutes of inactivity I see:

channel 1 closed 406 PRECONDITION_FAILED – delivery acknowledgement on channel 1 timed out. Timeout value used: 1800000 ms. This timeout value can be configured, see consumers doc guide to learn more 0 0

I am fairly certain I have acked all messages, and in our staging environment where I can control all traffic I can see that all queues are empty:

What else should I be checking to understand why I’m getting this timeout? Does it also happen when there is no activity for the timeout duration?