Mqtt client Nrf9160 Module

[Ukhan]

My nrf9160 isn't responsive to the AT commands for MQTT mentioned here. I want to know why is that so?
I've put certificates in the module from AWS-Iot core and flashed at_client example inside the nrf9160 and trying to send AT#XMQTTCON command to connect it to the broker. 

Am I missing something or Is this a work in progress and these commands aren't available yet? 
I want to make use to this mqtt client to connect to AWS-IoT instead of doing in in the application, I suppose that'll be possible as well.

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[Øyvind]

Hello,

First of all, what version of NCS are you working on?

 flashed at_client example inside the nrf9160 and trying to send AT#XMQTTCON command to

Have you tried with the Serial LTE modem application? The MQTT AT command is only available in this application. 

Edit: For AT commands that work with the AT client, please see the AT Commands documentation.

Kind regards,
Øyvind

[Ukhan]

NCS: v1.4.99, I suppose this is the latest.

I tried with Serial LTE modem application as well. 
Following the documentation, I send 

AT#XMQTTCON=0,"nrf91","","","myAWSendpoint.com",8883,123

ERROR

On nrf connect desktop app I can see that signal strength is fine and the module is awake as well. 

One weird thing is that on AWS-IoT core I can see that a connection was established in the Manage section where it shows connections graph.

[Ukhan]

Correct me if I am wrong but in the code the macro AT_MQTTCON_CONNECT is set to 1 while in the documentation it says 

AT#XMQTTCON=<op>[,<client_id>,<username>,<password>,<url>,<port>[,<sec_tag>]]

• The <op> parameter is an integer. It can accept one of the following values:

  • 0 - Connect to the MQTT broker.

  • 1 - Disconnect from the MQTT broker.

That seems to be contradictory. I debugged and it seemed to hit the connect case AT_MQTTCON_CONNECT case only when 1 was sent. And then it polls for CONACK where it returns error.

So basically this is happening on nrf Connect

[Øyvind]

Hello, 

Yes, you are correct. There seems to be a bug in the documentation which I will report. This also explains the ERROR you received in your last comment.

The MQTTEVT reports -128, which means "Socket is not connected".

[Ukhan]

Could you explain how do I fix that? Do I need to issue a different at command before that?
I was assuming all of this will be handled in the slm application.

[Øyvind]

Have you tested the MQTT connection using e.g. Simple MQTT sample? Have a look at the answer my colleague Heidi gives here.

Please make sure to use correct username, password and sec_tag for your certificates. Have you verified that you have added correct certificates?

[Ukhan]

I tried the simple one before and AWS-IoT example as well. I tried everything again.
And it seems to be a problem with the MNO as Farhang pointed out in the ticket you shared. 

Now, I have tried two different MNOs KT and SK Telecom(by configuring with AT commands) and both of them have a problem with socket connection. 

On AWS Cloudwatch I can see this 



The AWS-IoT example in the NCS, I tried that as well, with two different ports: 8333 and 443.
With 433 it gives the aws_iot_connect, error: -119 and with 8333 it gives E: mqtt_connect, error: -116.

Can you highlight what else can I try?

[Øyvind]

Are you able to provide a full log output when connecting to AWS-IoT? Both with 433 and 8333. I  will discuss this with our R&D team. What modem fw are you running? And what is the network provider that you use?

aws_iot_connect, error: -119 means "Connection already in progress", while mqtt_connect, error: -116 means "Connection timed out".