nRF7002 DK MQTT messages not received.

[mtrobregado]

Hi,

I have an nRF7002-DK. I am trying the MQTT over Wi-Fi following this blog below.

https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/implementing-mqtt-over-wi-fi-on-the-nrf7002-development-kit

I have a previous post regarding this and it did work one time. But, just today I tried again same procedure but I am not able receive the messages from the 

MQTT Dashboard Android app. I can see from the logs that the nRF7002-DK is connected to the MQTT broker, see below.

[00:02:00.018,341] <inf> MQTT_OVER_WIFI: broker_init: IPv4 Address found 91.121.93.94
[00:02:00.325,012] <inf> net_mqtt: client_connect: Connect completed
[00:02:00.634,368] <inf> MQTT_OVER_WIFI: mqtt_evt_handler: MQTT client connected
[00:02:00.634,399] <inf> MQTT_OVER_WIFI: subscribe: Subscribing to: devacademy/subscribe/topic44 len 28
[00:02:00.906,158] <inf> MQTT_OVER_WIFI: mqtt_evt_handler: SUBACK packet id: 1234

Also, at proj.conf I changed the the mqtt broker to broker.hivemq.com see below.

# Application

CONFIG_MQTT_PUB_TOPIC="devacademy/publish/topic4445"

CONFIG_MQTT_SUB_TOPIC="devacademy/subscribe/topic4445"

#Note If you notice that the test.mosquitto.org is unresponsive,

#there are several other public MQTT brokers that you can use (Ex: broker.hivemq.com at port 1883)

CONFIG_MQTT_BROKER_HOSTNAME="broker.hivemq.com"

CONFIG_MQTT_CLIENT_ID="a3ec5cba-4730-406c"

CONFIG_MQTT_BROKER_PORT=1883

At Kconfig file here are my changes below.

config MQTT_PUB_TOPIC

    string "MQTT publish topic"

    default "devacademy/publish/topic4445"

config MQTT_SUB_TOPIC

    string "MQTT subscribe topic"

    default "devacademy/subscribe/topic4445"

config MQTT_CLIENT_ID

    string "MQTT Client ID"

    help

      Use a custom Client ID string.

    default "a3ec5cba-4730-406c"

config MQTT_BROKER_HOSTNAME

    string "MQTT broker hostname"

    default "broker.hivemq.com"

I don't understand why I am still getting this log.

[00:02:00.634,399] <inf> MQTT_OVER_WIFI: subscribe: Subscribing to: devacademy/subscribe/topic44

I read some posts that I may need to change the protocol to MQTT 3.1.1, but I do not know where to set that.

Regards,

Markel

[mtrobregado]

I reversed the publish and subscribe at the MQTT Dashboard Android App before that is why it does not work. After I corrected the published and subscribed it worked.

I think the other issue with the program from the guide is it does not always connect to the mqtt broker. After some time it will connect. Sometimes it connects the first time.

[00:00:19.607,818] <err> net_mqtt_rx: [CID 0x20003894]: Transport read error: -116
[00:00:19.607,849] <inf> net_mqtt_sock_tcp: Closing socket 7
[00:00:19.607,940] <inf> MQTT_OVER_WIFI: MQTT client disconnected: -116
[00:00:19.607,971] <err> MQTT_OVER_WIFI: Error in mqtt_input: -116
[00:00:19.607,971] <inf> MQTT_OVER_WIFI: Disconnecting MQTT client
[00:00:19.608,001] <err> MQTT_OVER_WIFI: Could not disconnect MQTT client: -128
[00:00:19.608,001] <inf> MQTT_OVER_WIFI: Reconnecting in 60 seconds...
[00:01:19.939,208] <inf> net_mqtt: Connect completed
[00:01:20.258,087] <inf> MQTT_OVER_WIFI: MQTT client connected
[00:01:20.258,117] <inf> MQTT_OVER_WIFI: Subscribing to: devacademy/subscribe/topic44 len 28
[00:01:20.581,604] <inf> MQTT_OVER_WIFI: SUBACK packet id: 1234
[00:01:23.246,368] <err> net_mqtt_rx: [CID 0x20003894]: Connection closed.
[00:01:23.246,398] <inf> net_mqtt_sock_tcp: Closing socket 7
[00:01:23.246,490] <inf> MQTT_OVER_WIFI: MQTT client disconnected: -128
[00:01:23.246,490] <err> MQTT_OVER_WIFI: Error in mqtt_input: -128
[00:01:23.246,520] <inf> MQTT_OVER_WIFI: Disconnecting MQTT client
[00:01:23.246,520] <err> MQTT_OVER_WIFI: Could not disconnect MQTT client: -128
[00:01:23.246,551] <inf> MQTT_OVER_WIFI: Reconnecting in 60 seconds...

Regards,

Markel

[Håkon Alseth]

Hi Markel,

 

Could you try reducing "CONFIG_MQTT_KEEPALIVE" to see if this helps the scenario?

 

Kind regards,

Håkon

[mtrobregado]

Hi,

After many tests I confirmed that using test.mosquitto.org as MQTT broker is causing the MQTT disconnection. I do not know the reason.

I changed MQTT broker to broker.hivemq.com and it works now. I also slightly modified the code to handle unsuccessful MQTT broker connection.

Regards,

Markel

[Håkon Alseth]

Hi Markel,

 

mtrobregado said:

After many tests I confirmed that using test.mosquitto.org as MQTT broker is causing the MQTT disconnection. I do not know the reason.

I changed MQTT broker to broker.hivemq.com and it works now. I also slightly modified the code to handle unsuccessful MQTT broker connection.

I'm glad to hear that the connection is stable towards another broker.

test.mosquitto.org is a free service, which many people use, so the stability could potentially be an issue. Thank you so much for updating your case with a workaround, and its fun to see that your application works as expected!

 

I'll keep this stability issue in mind for the future as well.

 

Hope you have a wonderful day!

 

Kind regards,

Håkon