MQTT Sample Not Connecting on nRF9160 Board

[RodWatt]

Hi,

Sorry, i am new to MQTT so may be asking a stupid question, please bear with me. 

I am trying to run the MQTT sample (nrf\samples\net\mqtt) and get the following output

*** Booting nRF Connect SDK v3.5.99-ncs1-1 ***
[00:00:00.312,896] <inf> network: Bringing network interface up and connecting to the network
[00:00:00.505,187] <inf> nrf_modem_lib_trace: Trace thread ready
[00:00:00.506,500] <inf> nrf_modem_lib_trace: Trace level override: 2
[00:00:00.508,270] <err> lte_lc: Could not send AT command, error: 65536
[00:00:00.508,270] <err> lte_lc: Failed to set system mode and mode preference, err -14
+CEREG: 2,"01B0","081A1682",7,0,0,"11100000","11100000"
+CSCON: 1
+CSCON: 0
+CSCON: 1
+CGEV: ME PDN ACT 0,0
+CNEC_ESM: 50,0
+CEREG: 1,"01B0","081A1682",7,,,"00011110","00011011"
[00:00:15.113,403] <inf> network: Network connectivity established
+CSCON: 0
+CSCON: 1
+CSCON: 0
+CSCON: 1
+CSCON: 0
+CSCON: 1
+CSCON: 0
+CSCON: 1
[00:00:43.618,835] <err> mqtt_helper: mqtt_connect, error: -116
[00:00:43.618,865] <err> transport: Failed connecting to MQTT, error code: -116
+CSCON: 0

Looking at the cellular monitor, it suggests I am connecting?

Any pointers would be appreciated

Rod

[Øyvind]

Hello Rod, 

What MQTT broker are you trying to connect? And with what SIM card? 

From the start of the log, the LTE Link Controller reports the following

[00:00:00.508,270] <err> lte_lc: Could not send AT command, error: 65536
[00:00:00.508,270] <err> lte_lc: Failed to set system mode and mode preference, err -14

#define NRF_EFAULT 14           /**< Bad address */

#define NRF_ETIMEDOUT 116       /**< Connection timed out */

Here is my output after building the default MQTT sample (with nRF Connect SDK v2.6.0)

+CSCON: 1
+CGEV: ME PDN ACT 0,0
+CNEC_ESM: 50,0
+CEREG: 5,"8173","01165700",7,,,"11100000","11100000"
[00:00:09.843,292] <inf> network: Network connectivity established
[00:00:15.231,231] <inf> transport: Connected to MQTT broker
[00:00:15.231,262] <inf> transport: Hostname: test.mosquitto.org
[00:00:15.231,323] <inf> transport: Client ID: 350457791991456
[00:00:15.231,323] <inf> transport: Port: 1883
[00:00:15.231,353] <inf> transport: TLS: No
[00:00:15.231,414] <inf> transport: Subscribing to: 350457791991456/my/subscribe/topic
[00:00:15.303,253] <inf> transport: Subscribed to topic 350457791991456/my/subscribe/topic
+CSCON: 0
[00:01:00.324,523] <inf> transport: Published message: "Hello MQTT! Current uptime is: 60315" on topic: "350457791991456/my/publish/topic"
+CSCON: 1
+CSCON: 0
[00:02:00.324,707] <inf> transport: Published message: "Hello MQTT! Current uptime is: 120315" on topic: "350457791991456/my/publish/topic"
+CSCON: 1
+CSCON: 0

KInd regards,
Øyvind

[RodWatt]

Hi Øyvind,

I have not changed the code so am trying to connect to the default of test.mosquitto.org. I am using a Tesco PAYG SIM currently but have tried SIMS from EE and Vodafone. Can you recommend one? I am based in the UK.

Cheers,

Rod

[RodWatt]

Hi Øyvind,

I just outside Cambridge, in CB23 postcode. I have put the SIM card in a mobile phone and and seeing "4 bars" so I think Im getting a strong signal. Maybe I am using an incompatible SIM card. Can you recommend one for this area?

Does the MQTT demo use LTE-M or NBIOT?

Rod

[Øyvind]

From the initial post your device was connected to LTE-M (digit 7) on home network, i.e. the SIM providers network:
+CEREG: 1,"01B0","081A1682",7,,,"00011110","00011011"

More information on the CEREG command can be found here.

RodWatt said:

am using a Tesco PAYG SIM currently but have tried SIMS from EE and Vodafone. Can you recommend one?

For the UK there are two operators listed in the GSMA IoT Deployment map:

Telefonica for LTE-M

Vodafone for NB-IoT

Could you provide logs from your device using the Vodafone SIM? Most importantly the SIM need to support LTE-M and/or NB-IoT. You could have a go with Wireless Logic's roaming SIM'

Kind regards,
Øyvind

[RodWatt]

Here is the trace from the vodafone SIM. 

trace-2024-06-24T16-08-30.209Z.mtrace

[Øyvind]

Thanks for providing this trace. 

There seems to be an issue with the Vodafone SIM as it gets rejected from the network with message:

Roaming not allowed in this tracking area (13)

I would reach out to Vodafone and ask them about the coverage in your area. I reached out to our sales team in the UK yesterday regarding your case, and they informed me that O2 is the only one doing LTE-M in the UK, but there seems to be an issue with the SIM you were using. Best to try a O2 SIM to test with LTE-M. 

Kind regards,
Øyvind

[RodWatt]

Thanks Øyvind,

I talked to O2 and they told me that the Tesco SIM I have uses their network so it will act the same as an O2 SIM.

It seems to be connecting but I dont think the signal is strong enough.

trace-2024-06-25T09-53-38.262Z.mtrace

Rod

[Øyvind]

Yes, correct, the signal seems to be the issue here. From the modem trace I see that your connection times out. If O2 confirms that Tesco SIM should be fully supported, and your device is registered to home network (as it states), then I would suggest testing at other locations.

Could there be equipment close to your board/location causing interreference with the LTE signal?

[RodWatt]

Hi Øyvind,

I have managed to update my toolchain to v2.7.0-rc3. (I had previously tried to update to rc2 and rc1 but it kept flagging an error, so i was running v.2.6.1)

Updating to rc3 also enabled me to also update to the latest firmware.

Anyway, this has allowed me to connect correctly. I have not changed my location, I am still physically in the same place, still using a SIM from Tescos.

+CEREG: 2,"01B0","07C2B478",7
+CSCON: 1
+CGEV: ME PDN ACT 0,0
+CNEC_ESM: 50,0
+CEREG: 1,"01B0","07C2B478",7,,,"11100000","11100000"
[00:00:03.503,845] <inf> network: Network connectivity established
+CSCON: 0
+CSCON: 1
[00:00:13.781,951] <inf> transport: Connected to MQTT broker
[00:00:13.781,982] <inf> transport: Hostname: test.mosquitto.org
[00:00:13.782,043] <inf> transport: Client ID: 352656106650388
[00:00:13.782,043] <inf> transport: Port: 8883
[00:00:13.782,073] <inf> transport: TLS: Yes
[00:00:13.782,135] <inf> transport: Subscribing to: 352656106650388/my/subscribe/topic
[00:00:13.894,958] <inf> transport: Subscribed to topic 352656106650388/my/subscribe/topic
+CSCON: 0
+CSCON: 1
+CSCON: 0
[00:01:00.413,665] <inf> transport: Published message: "Hello MQTT! Current uptime is: 60404" on topic: "352656106650388/my/publish/topic"
+CSCON: 1
+CSCON: 0
+CSCON: 1
+CSCON: 0
[00:02:00.413,940] <inf> transport: Published message: "Hello MQTT! Current uptime is: 120404" on topic: "352656106650388/my/publish/topic"
+CSCON: 1
+CSCON: 0
+CSCON: 1
+CSCON: 0
+CEREG: 1,"01B0","081A1682",7,,,"11100000","11100000"
[00:03:00.414,215] <inf> transport: Published message: "Hello MQTT! Current uptime is: 180404" on topic: "352656106650388/my/publish/topic"
+CSCON: 1
+CSCON: 0

So, thanks for your help.

Regards,
Rod

PS my next step is to update the broker address, user name and password to allow me to connect to a different server but i will close this ticket and open a new one if required.