Re: [TCP/MQTT] Connection issue

Guillaume Paquet

Hello Michael,


Thanks for your prompt reply.

I just open this new issue:

However, I am not able to assign it to you.


Really thanks for your help on this case






De : Michael Scott <mike@...>
Envoyé : mercredi 11 décembre 2019 20:30
À : Guillaume Paquet <guillaume.paquet@...>; Guillaume Paquet via Lists.Zephyrproject.Org <>; devel@...
Objet : Re: [Zephyr-devel] [TCP/MQTT] Connection issue


Hello Guillaume,


On 12/11/19 11:19 AM, Guillaume Paquet wrote:

Hello Zephyr Community,


I found where something is wrong.

Indeed in net_context_get function, I saw that I reached CONFIG_NET_MAX_CONTEXTS (equal to 10 in my prj.conf).
For your information, I use UBLOX sara r4 driver (on zephyr 1.14.1 as I mentionned in my previous mail) and I wonder if contexts are well managed in this revision, especially when socket is closed ?


There could certainly be a bug in the socket offloading layer for UBLOX Sara R4 (I'm the maintainer for the current modem layer in Zephyr):


Can you open an issue here:


Please include as much information as you can (from this email series):
- Zephyr version: 1.14.1

- Sample used: samples/net/mqtt_publisher

- Firmware version on SARA R4 modem

- etc


And add me as "Assignee"




- Mike



Thanks in advance for your help


Best Regards,



De : devel@... <devel@...> de la part de Guillaume Paquet via Lists.Zephyrproject.Org <>
Envoyé : mercredi 11 décembre 2019 16:24
À : Guillaume Paquet <guillaume.paquet@...>; devel@... <devel@...>
Cc : devel@... <devel@...>
Objet : Re: [Zephyr-devel] [TCP/MQTT] Connection issue


And just to add some precision, I work on zephyr 1.14.1.






De : devel@... <devel@...> De la part de Guillaume Paquet via Lists.Zephyrproject.Org
Envoyé : mercredi 11 décembre 2019 13:50
À : devel@...
Cc : devel@...
Objet : [Zephyr-devel] [TCP/MQTT] Connection issue


Hello Zephyr community,


I contact you because I have an issue when I run mqtt_publisher example


I have the following issue when I have multiple mqtt connection/disconnection (through tcp transport_connect function)

[try_to_connect:233] mqtt_connect: -2 <ERROR>


I have this issue after 10 connection/disconnection. The eleventh one is always failing.

As I said you I saw that this is failing when I try to run mqtt_transport_connect(client); in client_connect.


My configuration is the following one :

·        MQTT (not secured)

·        TCP/IPv4

·        Broker on external server (not any issue on this one)


If you have any idea to help me


Thanks in advance


Best Regards



Guillaume  PAQUET – IoT Engineer

guillaume.paquet@...  -  02 40 18 50 91

1 Avenue Professeur Jean Rouxel – ZAC Fleuriaye

44470 CARQUEFOU – FRANCE                


Michael Scott
Embedded Software Engineer at
"microPlatforms™ for Connected Products"
E: mike@...

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