What to do when I don’t receive MQTT messages although ifm IO-Link-Master is connected?

This troubleshooting guide provides a step-by-step approach for connect ifm IO-link masters via sensorconnect.


There are no MQTT messages in MQTT Explorer, although the MQTT Explorer configuration is correct. See also:

Setting up the MQTT broker to see MQTT-messages


As a first step we take a look whether sensorconnect is running.

  1. Connect to the stack using OpenLens (Our Learn Guide or the Youtube Video)
  1. Open the logs of the sensorconnect Pod and see whether there are any error messages


Issue: Error message: “Neither MQTT nor Kafka output enabled”


This is repairable by opening the Values of the UMH release in OpenLens and looking for the sensorconnect indentations. Either mqtt-enable or kafka-enable needs to be true. Do note that mqtt is not anymore not fully supported on the newest versions and sensorconnect might still fail afterwards if you set mqtt-enable to true .

Issue: There are no error messages, but it can’t find any devices

{"log.level":"info","@timestamp":"2022-05-17T14:40:07.979Z","log.origin":{"file.name":"sensorconnect/main.go","file.line":71},"message":"This is sensorconnect build date: 2022-05-06 14:20:26","ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2022-05-17T14:40:07.982Z","log.origin":{"file.name":"sensorconnect/main.go","file.line":94},"message":"Starting with Kafka","ecs.version":"1.6.0"}
%4|1652798408.189|CONFWARN|rdkafka#producer-1| [thrd:app]: Configuration property group.id is a consumer property and will be ignored by this producer instance
%4|1652798408.586|CONFWARN|rdkafka#producer-2| [thrd:app]: Configuration property group.id is a consumer property and will be ignored by this producer instance
{"log.level":"info","@timestamp":"2022-05-17T14:40:08.677Z","log.origin":{"file.name":"sensorconnect/main.go","file.line":203},"message":"Scanning IP range:","ecs.version":"1.6.0"

Reviewing above logs. There are no error messages, but it didn’t find any device. Please assure that the IP-range is correct


Checking the IO-Link master and see that there is a physical network connection.

Therefore, it must mean that the sensorconnect microservice is not able to access the IO-Link master. It could be in a different network or there could be a firewall blocking the access. To troubleshoot you can try finding it in the network (port 80 will be open) using this guide:

Finding IP of VM

Or in general

Troubleshooting networking issues

At first it wasn’t:


By connecting the IO-Link master to the factory cube through a different port. It will appear in the network with for example the IP address


In OpenLens, is it possible to see that the sensorconnect Pod is now finding the device. (This might take a while.)


Last modified October 5, 2022: Historian article (#107) (5f30dc0)