Thanks! I was using 127.0.0.1 because that’s what other people were successfully using: github.com/knadh/listmonk/issues/1590#issuecommen…. I had tried variations of proxy_pass http://app:5870; because I’m running listmonk successfully on another server using proxy_pass http://app:9000;, but that is when nginx is running from inside the docker container:
I forgot to try proxy_pass http://listmonk_app:5870; though. I just tried that and I got the same error that I get with proxy_pass http://app:5870;.
Job for nginx.service failed because the control process exited with error code. See “systemctl status nginx.service” and “journalctl -xe” for details.