Failed MQTT Connection Error Code 3

[nico-fri]

I tried to send data with MKR NB to a MQTT Broker with following components:

• MKR NB 1500
• 1NCE card with active data plan

and used MKRNB and ArduinoMqttClient Libraries.

When I try to connect the MKR NB to the MQTT broker, I get ERROR-CODE 3 = Server unavailable. With the MKR 1010 Wifi the connection to the broker always works. Even with the program MQTT.fx and the same access data, the connection to the broker works without problems and data can be sent.

The connection with the MKR NB has already worked and now it gives the error without changes in the code again.

When I run the NBWebClient example sketch, I get the http request without any problems.

[ircole]

I'm seeing that error intermittently. I'm using the soft watchdog code to reset the processor when there is some hang and sometimes it will recover but in some cases I have to remove the battery (or if no battery the USB cable) to get it to work again. A few days ago I picked up the pre-release of the MKRNB library and before that it seems that the reset by the soft watchdog always recovered. Don't know if the problem is with the update library or something else. It's not uncommon to get this error as it's caused by a timeout on a write. Setting the timeout in NBClient write to 240000 helps but still get problems just not as frequently. Seems after a timeout on a send often the library code hangs in some loop and my code never gets control again which is the reason I use the software watchdog. My broker is a Mosquitto broker running on one of my systems and I can see in the log that the open socket works as the broker logs a New Connection message. Before updating the library I could run for days (with many watchdog restarts) but now I can't. Unfortunately I don't have a solution. At this very point in time I'm having success send messages to the broker but it quit earlier today and it took completely removing power from the 1500 to get it working again. AT+USOCR=6 +USOCR: 0 OK AT+USOCO=0,"207.40.144.108",1883 OK AT+USOWR=0,56,"103600044D51545404C2003C00174D4B52313530302D333532373533303930383630383038000773656E736F72730008747269636B68616D"NCClient send wait returns: -1 AT+USOCL=0 ERROR .CONNECT ERROR: 3 +UUSOCL: 0

[CptHolzschnauz]

try #84