MQTT binding - Error starting broker connection

I have OpenHab running on Ubuntu on a PC which grabs basic data from Weather Underground and plots it. Separately I have a raspberry pi connected to a temperature and humidity sensor which is intended to publish data to a topic held by a broker on the OpenHab PC.

The MQTT binding has been copied to the addons folder.

MQTT Tansport is setup in openhab.cfg with:
mqtt:msgs.url=tcp://localhost:1883

However, when I launch the OpenHab runtime I get an Error starting broker connection after MQTT initialisation. The relevant part of the openhab.log is copied below. I suspect this might be a permissions issue?

Error log:
2015-12-18 07:00:14.058 [INFO ] [.o.core.internal.CoreActivator] - openHAB runtime has been started (v1.7.1).
2015-12-18 07:00:17.222 [INFO ] [o.o.i.s.i.DiscoveryServiceImpl] - mDNS service has been started
2015-12-18 07:00:17.439 [INFO ] [o.o.i.s.i.DiscoveryServiceImpl] - Service Discovery initialization completed.
2015-12-18 07:00:17.459 [INFO ] [.io.transport.mqtt.MqttService] - MQTT Service initialization completed.
2015-12-18 07:00:17.461 [INFO ] [o.i.t.m.i.MqttBrokerConnection] - Starting MQTT broker connection ‘msgs’
2015-12-18 07:00:17.626 [ERROR] [.io.transport.mqtt.MqttService] - Error starting broker connection
org.eclipse.paho.client.mqttv3.MqttException: Unable to connect to server
at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:75) ~[na:na]
at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:538) ~[na:na]
at java.lang.Thread.run(Thread.java:745) ~[na:1.8.0_66]
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:1.8.0_66]
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_66]
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_66]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_66]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_66]
at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_66]
at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:66) ~[na:na]
… 2 common frames omitted

This suggests that there is no MQTT broker running on localhost on port 1883. If you are using mosquitto, make sure it’s configured correctly to listen on port 1883 (no encryption) and that it’s being started with the system. mosquitto can be configured to listen for ssl and tcp clients simultaneously on different ports, if needed.

Thanks Watou. You were right - there was an error in the mosquitto config file. The port was set to 1833 instead of 1883.

hi I have a same issue with same exact error i double check the mqtt.cfg every things seems to be ok

2017-04-07 12:05:43.951 [INFO ] [t.mqtt.internal.MqttBrokerConnection] - Starting MQTT broker connection 'mosquitto'
2017-04-07 12:05:44.184 [ERROR] [penhab.io.transport.mqtt.MqttService] - Error starting broker connection
Unable to connect to server (32103) - java.net.ConnectException: Connection refused (Connection refused)
        at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:75)[183:org.openhab.io.transport.mqtt:1.9.0]
        at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:538)[183:org.openhab.io.transport.mqtt:1.9.0]
        at java.lang.Thread.run(Thread.java:745)[:1.8.0_121]


Caused by: java.net.ConnectException: Connection refused (Connection refused)
        at java.net.PlainSocketImpl.socketConnect(Native Method)[:1.8.0_121]
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)[:1.8.0_121]
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)[:1.8.0_121]
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)[:1.8.0_121]
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)[:1.8.0_121]
        at java.net.Socket.connect(Socket.java:589)[:1.8.0_121]
        at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:66)[183:org.openhab.io.transport.mqtt:1.9.0]

if I set mosquitto on verbose mode (mosquitto -v) then i start getting values in UI and able to connect mqtt.fx and even in log file starting to show incoming data

can any one help

So for me, I had to go into the karaf console, delete the mqtt settings to get it to work. Also I just had to specify url, user and password to get it to work