Remove an old MQTT broker clienid

  • Platform information:
    *Synology Docker
    • openHAB version:3.20
  • Issue of the topic: Remove old MQTT broker

In my openhab log i have an error : Starting MQTT broker connection to ‘’ with clientid d3b1a914-eff9-4661-bd22-f161d2c325.
It seems it is an old MQTT broker, but i cannot find it my things to remove it.
I can see my working MQTT broker:

label: MQTT Broker
thingTypeUID: mqtt:broker
lwtQos: 0
publickeypin: true
clientid: 2c97597f-eaa1-4d4b-8e88-1a4784d04955
keepAlive: 60
qos: 0
reconnectTime: 60000
secure: false
certificatepin: true
lwtRetain: true
enableDiscovery: true
location: Office

The working MQTT broker has a completely different clientid

I already try deleting cache and temp folder data in the userdata folder, but the error keep coming back ever few minutes.

How can i get rid of this “old” clientid ?



Similar to this one OH3 MQTT changing broker information ?
I would try to use the API explorer, list all things to check if it is listed there.
You then should be able to delete it via the API explorer or using the karaf console ( which also can be used to list things ).
You also could use an editor and check content of the jsondb file(s). This is most probably not recommended at least you need to be prepared ( backup ) for hickups …

You might have a Systembroker Thing, this is not the same as a regular broker and does not get listed in the same places (but is not wanted in OH3).

Ok, that was it.

On the “other services” , system MQTT broker, i had some data.
Blanked everything and saved (there is no remove)
Restart the openhab and checked the logs after 30 minutes.
Error is gone.

Thanks for you help.


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