How did I fix «Unable to connect to epmd» for RabbitMQ?

194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: DIAGNOSTICS
194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: ===========
194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: attempted to contact: [rabbit@194]
194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: rabbit@194:
194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: * unable to connect to epmd (port 4369) on 194: badarg (unknown POSIX error)
194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: * node name: 'rabbitmqcli-16077-rabbit@194'
194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: * effective user's home directory: /var/lib/rabbitmq
194.39.164.132.srvlist.ukfast.net rabbitmqctl[16077]: * Erlang cookie hash: c+uWM5j/XbrtAkbQtWa36Q==
194.39.164.132.srvlist.ukfast.net systemd[1]: Failed to start RabbitMQ broker.

I have fixed it my creating the etc/rabbitmq/rabbitmq-env.conf file with the following contents:

HOSTNAME=localhost

stackoverflow.com/a/45475646
github.com/tradefurniturecompany/server/issues/3