I am not using Sierra Wireless’ MQTT Client, I am using the paho MQTT library within my application.
Here is the mosquitto server receiving a message from the paho standalone client program. Unfortunately I’m not set up to run my application on the SW at this time.
$ /snap/mosquitto/current/usr/sbin/mosquitto -v -c /snap/mosquitto/current/default_config.conf
1618337359: mosquitto version 1.6.14 starting
1618337359: Config loaded from /snap/mosquitto/current/default_config.conf.
1618337359: Opening ipv4 listen socket on port 1883.
1618337359: Opening ipv6 listen socket on port 1883.
1618337359: mosquitto version 1.6.14 running
1618337682: New connection from 127.0.0.1 on port 1883.
1618337682: New client connected from 127.0.0.1 as paho-c-pub (p2, c1, k10).
1618337682: No will message specified.
1618337682: Sending CONNACK to paho-c-pub (0, 0)
1618337682: Received PUBLISH from paho-c-pub (d0, q0, r0, m0, 'mytopic', ... (5 bytes))
1618337682: Received DISCONNECT from paho-c-pub
1618337682: Client paho-c-pub disconnected.
$ paho_c_pub -c localhost -t mytopic -m hello