@masmat please check your MQTT configuration. You're receiving an exception because it's trying to set "1883.0" for the value port.

@jogant Yeah. There are still some problems with 2.3 to fix. The binding works fine within the development IDE, but only there. I'm still looking into it.

@andre_m87 & @MasMat : I found a solution and indeed the MQTT implementation in OH2 (ESH) changed. This was a hard nut to crack, so it took me a while.

Here are the steps you need to do:

1. Rename: org.eclipse.smarthome.mqtt.cfg to org.eclipse.smarthome.mqttbroker.cfg
2. Change the content to:

name=mosquitto
host=192.168.2.3
secure=false
port=1883
username=USERNAME
password=PASSWORD
retain=false

If you're using a secure connection (SSL): change secure to true and use the correct port.

Another intersting feature in OpenHAB 2.3 is the embedded broker, so there is no need to have a separate MQTT server up and running.

@andre_m87 & @MasMat : I have the same problem here. Looks like a change in the OpenHAB MQTT implementation.
I'm working on it.

@julian-kröhl oh, you have found a really old thread.
I suggest you to go with the binding or with the MQTT gateway.

If you want to use the binding have a look here: https://github.com/tobof/openhab2-addons/wiki

@donny152 The version 2.2 / 2.3 in the binding name represents the code base the binding is developed to. The current code base is 2.3 so this is the way to go. If you're starting out, just use 2.3.

@dbagioni Is there an error message in the log to the time the gateway changes its state to offline?

Have you considered using the binding for OH2 and MySensors?

Please post (copy and paste) the exact error message from karaf console.

Is the Uno registered by Linux? dmesg, lsusb. Please check the spelling: is it ACM0 or AMC0?

@jogant please enable debug output with log:set DEBUG org.openhab.binding.mysensors and post the debug output here. I'll look at it.