Hello !
I just hosted a simple MQTT Broker with HTTP over TLS (node aedes) and tried to access it with MQTT.js via TCP port (1883), but every time I got a timeout locally.
Maybe I shouldn’t try to test it locally and host another client and give it a try?
Render only listens to standard HTTP ports (80/443) for internet requests to Web Services. Private networking between services is possible, say for example if a worker running on another Render Service connected to that broker ( Private Network – Render Docs ).