A wired producer connection timeout issue

A Kafka producer frequently timeout when connecting to a remote Kafka cluster while producers on other machine (same data center) can connect to the Kafka cluster with no problem.  From the monitoring,  the ProductQueueSize is always full and message sent rate is low. We use Kafka 0.8. We set "batch.num.messages=10000" and "queue.buffering.max.ms=5000". 
 
Here is the error message:
[2014-08-08 17:52:02,786] ProducerSendThread producer.SyncProducer ERROR Producer connection to kafka-XXX.com:9092 unsuccessful
java.net.ConnectException: Connection timed out
        at sun.nio.ch.Net.connect(Native Method)
        at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:525)
        at kafka.network.BlockingChannel.connect(BlockingChannel.scala:57)
        at kafka.producer.SyncProducer.connect(SyncProducer.scala:146)
        at kafka.producer.SyncProducer.getOrMakeConnection(SyncProducer.scala:161)
        at kafka.producer.SyncProducer.kafka$producer$SyncProducer$$doSend(SyncProducer.scala:68)
        at kafka.producer.SyncProducer.send(SyncProducer.scala:112)
        at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:53)
        at kafka.producer.BrokerPartitionInfo.updateInfo(BrokerPartitionInfo.scala:82)
        at kafka.producer.async.DefaultEventHandler$$anonfun$handle$1.apply$mcV$sp(DefaultEventHandler.scala:67)
        at kafka.utils.Utils$.swallow(Utils.scala:187)
        at kafka.utils.Logging$class.swallowError(Logging.scala:105)
        at kafka.utils.Utils$.swallowError(Utils.scala:46)
        at kafka.producer.async.DefaultEventHandler.handle(DefaultEventHandler.scala:67)
        at kafka.producer.async.ProducerSendThread.tryToHandle(ProducerSendThread.scala:104)
        at kafka.producer.async.ProducerSendThread$$anonfun$processEvents$3.apply(ProducerSendThread.scala:87)
        at kafka.producer.async.ProducerSendThread$$anonfun$processEvents$3.apply(ProducerSendThread.scala:67)
        at scala.collection.immutable.Stream.foreach(Stream.scala:548)
        at kafka.producer.async.ProducerSendThread.processEvents(ProducerSendThread.scala:66)
        at kafka.producer.async.ProducerSendThread.run(ProducerSendThread.scala:44)