kafka Failed to send messages after 3 tries problem solving

Error using Kafka_2.11-0.9.0.0 producer API :

Exception in thread "main" kafka.common.FailedToSendMessageException: Failed to send messages after 3 tries.

Here is the producer code:

import java.util.Properties;

/**
 * Kafka producer API
 */
public class KafkaProducer extends Thread {
    private String topic;
    private Producer<Integer, String> producer;

    public KafkaProducer(String topic) {
        this.topic = topic;

        Properties properties = new Properties();
        properties.put("metadata.broker.list", KafkaProperties.BROKER_LIST);
        properties.put("serializer.class", "kafka.serializer.StringEncoder");
        properties.put("request.required.acks", "1");

        producer = new Producer<Integer, String>(new ProducerConfig(properties));
    }

    @Override
    public void run() {
        int messageNum = 1;

        while (true) {
            String message = "message_" + messageNum;
            producer.send(new KeyedMessage<Integer, String>(topic, message));
            System.out.println("send: " + message);

            messageNum++;

            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace ();
            }
        }
    }

    public static void main(String[] args) {
        new KafkaProducer(KafkaProperties.TOPIC).start();
    }
}

After some research, it was found that

# Hostname the broker will advertise to producers and consumers. If not set, it uses the
# value for "host.name" if configured.  Otherwise, it will use the value returned from
# java.net.InetAddress.getCanonicalHostName().
advertised.host.name=hadoop

It must be configured here. The remote connection is based on this configuration to find the broker. The default is localhost.