It seems like connectivity is problematic, even though the networks
appear to be configured correctly:

> [ioredis] Unhandled error event: Error: connect ECONNREFUSED 172.22.0.2:6739
> at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1595:16)

For now, I disable pointing the queue host to Redis to avoid it.
It should be investigated.

People who enable Hookshot's new experimental encryption may encounter
this also.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3042