Unable to Publish message on MQTT Topic in IBM Websphere MQ from WSO2 EI 6.3.0

Description: I am using WSO2 EI 6.3.0 to publish a message on a topic via MQTT in IBM Websphere MQ v8.0.0.5. . I am following this [link]. (https://docs.wso2.com/display/EI640/Sample+272%3APublishing+and+Subscribing+using+WSO2+ESB%27s+MQ+Telemetry+Transport).
When I am calling this I am getting the following error. IT doesn't matter if I define the client id or not the error is the same. Error:

2019-03-22 12:39:58,350] [] ERROR - MqttSender Exception occurred at sending message
Invalid client ID (2)
        at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:31)
        at org.eclipse.paho.client.mqttv3.internal.ClientState.notifyReceivedAck(ClientState.java:973)
        at org.eclipse.paho.client.mqttv3.internal.CommsReceiver.run(CommsReceiver.java:128)
        at java.lang.Thread.run(Thread.java:748)
[2019-03-22 12:39:58,355] [] ERROR - MqttSender Error while disconnecting the mqtt client
Client is disconnected (32101)
        at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:31)
        at org.eclipse.paho.client.mqttv3.internal.ClientComms.disconnect(ClientComms.java:467)
        at org.eclipse.paho.client.mqttv3.MqttAsyncClient.disconnect(MqttAsyncClient.java:703)
        at org.eclipse.paho.client.mqttv3.MqttAsyncClient.disconnect(MqttAsyncClient.java:672)
        at org.eclipse.paho.client.mqttv3.MqttAsyncClient.disconnect(MqttAsyncClient.java:679)
        at org.eclipse.paho.client.mqttv3.MqttClient.disconnect(MqttClient.java:258)
        at org.apache.axis2.transport.mqtt.MqttSender.sendMessage(MqttSender.java:132)
        at org.apache.axis2.transport.base.AbstractTransportSender.invoke(AbstractTransportSender.java:112)
        at org.apache.axis2.engine.AxisEngine$TransportNonBlockingInvocationWorker.run(AxisEngine.java:626)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
[2019-03-22 12:39:58,374] []  INFO - AxisEngine [MessageContext: logID=f612e1cbac90fbe39bbbe8c4295f02207affcd67c7ead122] Exception occurred at sending message
[2019-03-22 12:39:58,388] [] ERROR - AsyncCallback Exception occurred at sending message
org.apache.axis2.AxisFault: Exception occurred at

My Proxy Service Code:

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
       name="TestMQTTTopicPublishing"
       startOnLoad="true"
       statistics="disable"
       trace="disable"
       transports="jms">
   <target>
      <inSequence>
         <log level="full"
              separator="===------MQTT Service Started. Message Received---===="/>
         <property action="remove" name="TRANSPORT_HEADERS" scope="axis2"/>
         <property name="FORCE_SC_ACCEPTED"
                   scope="axis2"
                   type="STRING"
                   value="true"/>
         <property name="OUT_ONLY" scope="default" type="STRING" value="true"/>
         <call>
            <endpoint>
               <address uri="mqtt:/TestMQTTTopicPublishing?mqtt.server.host.name=localhost&amp;mqtt.server.port=1883&amp;mqtt.topic.name=FLIGHTELEGRAM.TOPIC&amp;mqtt.subscription.qos=2&amp;mqtt.blocking.sender=true&amp;mqtt.client.id=esbtestsender&amp;mqtt.session.clean=true&amp;mqtt.message.retained=true"/>
            </endpoint>
         </call>
         <log separator="=======-----Message Successfully Sent To MQTT Topic----====="/>
      </inSequence>
   </target>
   <parameter name="transport.jms.Destination">FLIGHTTELEGRAMS.QUEUE</parameter>
   <parameter name="transport.jms.ContentType">
      <rules xmlns="">
         <jmsProperty>contentType</jmsProperty>
         <default>application/xml</default>
      </rules>
   </parameter>
   <description/>
</proxy>

Also find attached the configuration of the Telemetry Channel in the IBM Websphere MQ MQTTChannelPNG

Please let me know what can I do to further narrow down the error or solve the problem. Thanks. .

Suggested Labels:

6.3.0, Type/Bug, MQTT, IBMWebsphere MQ

Affected Product Version: WSO2 EI 6.3.0

OS, DB, other environment details and versions:
Windows 10.

wso2 / product-ei

Unable to Publish message on MQTT Topic in IBM Websphere MQ from WSO2 EI 6.3.0 #3398