RE: Problem -116 error using mqtt protocal to connect EMQX broker server(GCP) in nRF9151 board

Junyoung Jeon — Fri, 27 Jun 2025 16:56:34 GMT

Thank you for helping me out. I solved this problem. Appreciate it.

Best regards,

Jeon

RE: Problem -116 error using mqtt protocal to connect EMQX broker server(GCP) in nRF9151 board

Øyvind — Fri, 27 Jun 2025 07:39:43 GMT

[quote user="Junyoung Jeon"]Yes I can send the datas from my computer to "mqtt.nordicsemi.academy"[/quote]

If this works, then the issue sounds to be with the EMQX host IP, and not an issue with the nRF9151

[quote user="Junyoung Jeon"]Should I try using Mosquitto?[/quote]

The reason for why I suggest this is to verify that you are able to connect to the EMQX host IP and if the issue is on the broker side or on the nRF9151 side.

[quote user="Junyoung Jeon"]do you know why it says -12 or -116? I changed a liittle bit in broker_init() now it says -12 error[/quote]

These error codes are found in e.g. nrfxlib/nrf_modem/include/nrf_errno.h.

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

#define NRF_ENOMEM 12 /**< Not enough space */

Not enough space could indicate that the EMQX broker needs certificates that are larger than 2k, part of the limitation of the device:

*** Limitations
***************
- TLS and DTLS
- Secure socket buffer size is 2kB.
- Maximum length of DTLS datagram is 1kB.
- One TLS handshake at a time is supported.
- Concurrent secure connections
- Maximum server certificate chain size has a limit of 4kB.
- Two active connections are supported when serialized DTLS connection exists.
- Two active connections are supported when any client certificate size is over 1kB.
- Two active connections are supported when GNSS acquisition is active.
- Three active connections are supported when client certificate sizes are 1kB or less.
- Four serialized DTLS connections are supported.
- Server certificate expiry time is not verified.
- pkcs#8 is not supported.
- Maximum number of supported credentials is 32. The actual amount depends on the size of
credentials as the memory area reserved for credentials may be a limiting factor as well.
- TLS is not supported when the socket is configured in TCP server mode.
- IP fragmentation and reassembly are not supported.
- It is recommended to free the modem resources by closing unused network sockets and by undefining
unused PDN connections with AT+CGDCONT.
- Maximum number of raw sockets is 4.
- User plane data is supported in Cat M1 mode only.
- Non-IP Data Delivery (NIDD) feature is verified only for NB-IoT. NIDD for LTE-M is not supported.
- The number of ownership keys is restricted to one. Multiple instances are not allowed.

Perhaps the MQTT sample would be a better starting point for more advanced MQTT connections.

Kind regards,
Øyvind

RE: Problem -116 error using mqtt protocal to connect EMQX broker server(GCP) in nRF9151 board

Junyoung Jeon — Thu, 26 Jun 2025 16:42:12 GMT

Hello,

Thank you for reply. Yes I can send the datas from my computer to "mqtt.nordicsemi.academy" which is the address Nordic provides. Should I try using Mosquitto? and do you know why it says -12 or -116? I changed a liittle bit in broker_init() now it says -12 error

Best regards,

Jeon

RE: Problem -116 error using mqtt protocal to connect EMQX broker server(GCP) in nRF9151 board

Øyvind — Thu, 26 Jun 2025 08:30:17 GMT

Hello,

[quote user=""]So I changed hostname to EMQX host IP.[/quote]

Are you able to access this IP from your computer? I.e. can you use Mosquitto to send message from your computer to this MQTT broker?

Kind regards,
Øyvind