mqtt_simple error -57

[xuan0802]

Hi guys, I am developing an mqtt-based app using board nrf9160. I tested the mqtt_simple example but it does not work. Here is my setup.

+ Broker server: test.mosquitto.org --> I have tested this broker and it works all time
+ nrf9160 firmware version is 1.2, I have tested with both NRF SDK ver1.2 and current master version

I always got this error when checking log from Link monitor:
The MQTT simple sample startedLTE Link Connecting ...
+CEREG: 2,"A794","047EFC15",9,0,0,"11100000","11100000"
+CEREG: 1,"A794","047EFC15",9,,,"11100000","11100000"
LTE Link Connected!
IPv4 Address found 5.196.95.208
+CEREG: 1,"A794","047EFC17",9,,,"11100000","11100000"
+CEREG: 1,"A794","047EFC15",9,,,"11100000","11100000"
ERROR: mqtt_live -57
Disconnecting MQTT client...
Could not disconnect MQTT client. Error: -57

I tested many times, LTE connection is ok, server is ok but mqtt_live always shows error ...

Thanks you very much for your help

[xuan0802]

Please, any help from Nordic Semi guys

[Heidi]

Hi! 

I am assigned to this case and have been looking into it. 

I am not able to reproduce your issue, so I will need you to do some debugging.

Go into the mqtt_ping() function and add debugging messages like this (MQTT_TRC("Text");) to figure out which of the functions are returning error code -57. then add CONFIG_MQTT_LOG_LEVEL_DBG to the prj.conf file. 

 Are you trying to connect with LTE-M or NB-IoT?

Best regards,

Heidi

[xuan0802]

Thank you for your response, luckily, I run the sample with the current master version of SDK and It works.

[Heidi]

That's good to hear! I will close this case then. :)