simulated-device java例子抛异常 java.io.IOException: Error initializing MQTT connection:MqttException

[weixin_38056080]

我是完全按照官网的步骤(https://www.azure.cn/documentation/articles/iot-hub-java-java-getstarted/)写的simulated-devicejava例子,运行时抛异常
Exception in thread "main" java.io.IOException: Error initializing MQTT connection:MqttException
at com.microsoft.azure.iothub.transport.mqtt.MqttIotHubConnection.open(MqttIotHubConnection.java:139)
at com.microsoft.azure.iothub.transport.mqtt.MqttTransport.open(MqttTransport.java:84)
at com.microsoft.azure.iothub.DeviceClient.open(DeviceClient.java:175)
at com.mycompany.app.App.main(App.java:29)
而运行用C#写的例子就没问题(https://www.azure.cn/documentation/articles/iot-hub-csharp-csharp-getstarted/),不知是什么原因呢?