Unable to execute the MQQT TestStep using groovy script in ReadyAPI.

Hi Team,
I am unable to execute the MQTT Test Step using groovy script.Same scripts successfully executes the rest/soap test step but it returns cancel in the test logs. please suggest me the way. 

Here my script;

def result = context.testCase.testSteps["1- Publishing Ready State"].run(testRunner, context).getStatus();