I have a very same problem with mcginnda I try to config kafka broker support PLAINTXT and SSL at the same time,with server.properties config like these: listeners=PLAINTEXT://test-ip:9092,SSL://test-ip:9093 advertised.listeners=PLAINTEXT://test-ip:9092,SSL://test-ip:9093 advertised.host.name=test-ip delete.topic.enable=true ssl.keystore.location=/kafka/ssl/server.keystore.jks ssl.keystore.password=test1234 ssl.key.password=test1234 ssl.truststore.location=/kafka/ssl/server.truststore.jks ssl.truststore.password=test1234 ssl.client.auth = required ssl.enabled.protocols = TLSv1.2,TLSv1.1,TLSv1 ssl.keystore.type=JKS ssl.truststore.type=JKS ssl.secure.random.implementation=SHA1PRNG   and now, I try to use a consumer client to connect kafka server, but it not work.   in server.log, there is a lot of error like this. [2018-12-20 15:58:42,295] ERROR Processor got uncaught exception. (kafka.network.Processor) java.lang.ArrayIndexOutOfBoundsException: 18 at org.apache.kafka.common.protocol.ApiKeys.forId(ApiKeys.java:68) at org.apache.kafka.common.requests.AbstractRequest.getRequest(AbstractRequest.java:39) at kafka.network.RequestChannel$Request.<init>(RequestChannel.scala:79) at kafka.network.Processor$$anonfun$run$11.apply(SocketServer.scala:426) at kafka.network.Processor$$anonfun$run$11.apply(SocketServer.scala:421) at scala.collection.Iterator$class.foreach(Iterator.scala:742) at scala.collection.AbstractIterator.foreach(Iterator.scala:1194) at scala.collection.IterableLike$class.foreach(IterableLike.scala:72) at scala.collection.AbstractIterable.foreach(Iterable.scala:54) at kafka.network.Processor.run(SocketServer.scala:421) at java.lang.Thread.run(Thread.java:748)   and consumer DEBUG error like this: 2018-12-20 16:04:08,103 DEBUG ZTE org.apache.kafka.common.network.Selector TransactionID=null InstanceID=null [] Connection with test-ip/110.10.10.100 disconnected [Selector.java] [307] java.io.EOFException: null at org.apache.kafka.common.network.NetworkReceive.readFromReadableChannel(NetworkReceive.java:99) at org.apache.kafka.common.network.NetworkReceive.readFrom(NetworkReceive.java:71) at org.apache.kafka.common.network.KafkaChannel.receive(KafkaChannel.java:160) at org.apache.kafka.common.network.KafkaChannel.read(KafkaChannel.java:141) at org.apache.kafka.common.network.Selector.poll(Selector.java:286) at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:270) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.clientPoll(ConsumerNetworkClient.java:303) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:197) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:187) at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:877) at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:829) at com.zte.polling.provider.kafka.KafkaClientProvider$$anonfun$receiveMessage$1$$anonfun$apply$mcV$sp$2.apply(KafkaClientProvider.scala:59) at com.zte.polling.provider.kafka.KafkaClientProvider$$anonfun$receiveMessage$1$$anonfun$apply$mcV$sp$2.apply(KafkaClientProvider.scala:57) at scala.collection.Iterator$class.foreach(Iterator.scala:727) at com.zte.nfv.core.InfiniteIterate.foreach(InfiniteIterate.scala:4) at com.zte.polling.provider.kafka.KafkaClientProvider$$anonfun$receiveMessage$1.apply$mcV$sp(KafkaClientProvider.scala:57) at com.zte.polling.provider.kafka.KafkaClientProvider$$anonfun$receiveMessage$1.apply(KafkaClientProvider.scala:54) at com.zte.polling.provider.kafka.KafkaClientProvider$$anonfun$receiveMessage$1.apply(KafkaClientProvider.scala:54) at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24) at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24) at scala.concurrent.impl.ExecutionContextImpl$$anon$3.exec(ExecutionContextImpl.scala:107) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)   ... View more