mqtt_connect(&client) does not return any value during operation, and the program is stuck in mqtt_connect(&client) and does not come out

Hi,

There's several configuration(s) and function calls missing from the partial code that you posted, so I am unable to test your scenario. Do you see the same issue with for instance mqtt_simple sample?

Kind regards,

Håkon

Call mt_mqtt_connect() in this function and find that the function has no return value. The program stops in this function. According to the log print information, the program stops in the function err = mqtt_connect(&client).

Hello, I use USB to serial port to test. When I use uart0, the baud rate is 115200. Are you sure you use uart1 to obtain the modem trace at 1M baud rate? I use ncs1.5.1. What tutorial how to get modem trace?

Hi,

Please see the documentation for how to enable traces:

https://infocenter.nordicsemi.com/topic/ug_trace_collector/UG/trace_collector/intro.html?cp=10_3_3

Kind regards,

Håkon

Hi,

this is my modem trace during the process of retesting the problem.

The problem was reproduced at the end of the test。

Hi,

Thank you very much for the trace.

It shows that the application throughput is limited by network itself, ie. that the link is not fast enough to get anything through, so the buffers fill up inside the libmodem library.

There has been newly released versions of libmodem that has addressed these issues, but these will require you to upgrade to a newer version of ncs.

This is the version that was tagged with ncs v1.5:

https://github.com/nrfconnect/sdk-nrfxlib/blob/v1.8.0/nrf_modem/doc/CHANGELOG.rst#nrf_modem-101

So you can try to manually update to "nrf_modem" v1.0.3, and possibly also update to the newest modem firmware v1.2.7, as this also includes bugfixes.

Kind regards,

Håkon

Hi,

I am very glad to receive your reply. Unfortunately, we have such a problem, because our customers are currently running devices using ncs1.3.0 and modem v1.2.3, and ncs1.3.0 does not support modem upgrades , So according to what you said, the modem needs to be upgraded to 1.2.7. This method cannot be achieved. Is there any way to solve this problem without upgrading the modem?

Hi,

I am very glad to receive your reply. Unfortunately, we have such a problem, because our customers are currently running devices using ncs1.3.0 and modem v1.2.3, and ncs1.3.0 does not support modem upgrades , So according to what you said, the modem needs to be upgraded to 1.2.7. This method cannot be achieved. Is there any way to solve this problem without upgrading the modem?