Unable to publish to custom $aws MQTT topic in Losant broker

Bug Report
1

Hi,
I have a Milestone/Ursalink UC3452 cellular modem that has a built in MQTT client, and I am able to authenticate with the Losant broker as stipulated in the doc guidance, but when it tries to publish to their hard-coded “$aws/things/6123A1514245/shadow/get” topic, the Losant broker disconnects this device say it is not allowed to publish to this topic. However, there is nothing in the Losant MQTT doc’s saying this isn’t permitted, other than a reference to $SYS topics here - https://docs.losant.com/mqtt/overview/#losant-mqtt-topics

Are any MQTT topics starting with ‘$’ prohibited? If so your documentation needs to be much clearer on this thanks.
dollaraws-things-6123A1514245-shadow-get

Modem access key and MQTT topic
Modem access key and MQTT topic768×451 34.2 KB

Regards,
Andrew.

5

@Andrew_Leckie1 we follow the standard MQTT best practices of disallowing publishing to any topic beginning with a $. When you attempt to publish to a disallowed topic, the Losant Broker will disconnect the device that attempted to publish the message.

We’ll update the documentation based on your feedback to call out that all topics beginning with $ - not just $SYS - are disallowed. Sorry for the confusioin.