borpin
(Brian Orpin)
2
Can I check - when you say EmonCMS do you mean emoncms.org?
EmonCMS is the software that runs on the EmonPi, emoncms.org, and any other machine you like to install it on.
You can only input data to emoncms.org via the HTTP API not MQTT.

You can see from the diagram on that link that the remote emoncms.org is accessible via HTTP from emonhub.
You could also use the Node-Red emoncms node to take the MQTT data and publish it to emoncms.org (again using the HTTP API).
@TrystanLea as I wrote this, I wondered if it was possible to use emonhub as an interface MQTT → HTTP; i.e. pick up an MQTT base topic say to_emoncm_org and publish on the HTTP interface to emoncms.org?