ECONNREFUSED using placeholder about placeholder HOT 1 OPEN

That's very odd, I suspect it's something to do with how your network is configured.

It's possible that your host machine can access the port while another container cannot.

Couple things worth checking:

• In your comment I see that the service is bound to the host/interface age5, normally I'd expect 0.0.0.0 (all interfaces) or 127.0.0.1 (local interface), not sure what age5 is, this is a non-standard configuration which might be causing issues.
• The docker networking is based on hostnames, I've had issues in the past when adding a new service to docker-compose.yml, services which are already running cannot resolve the new host name, this can usually be resolved by bringing all the containers down and up again

Let me know how you get on

from placeholder.