title: Kafka Schema Registry - Error starting the schema registry (io.confluent.kafka.schemaregistry.rest.SchemaRegistryRestApplication)
body: <p>i'm trying to configure schema registry to work with SSL, i have already zookeeper and kafka brokers working with the same SSL keys. 
  but whenever i start the schema-registry i get the following error </p>
  
  <pre><code>ERROR Error starting the schema registry   (io.confluent.kafka.schemaregistry.rest.SchemaRegistryRestApplication)
   io.confluent.kafka.schemaregistry.exceptions.SchemaRegistryInitializationException: Error     initializing kafka store while initializing schema registry
      at     io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.init(KafkaSchemaRegistry.java:224)
      at io.confluent.kafka.schemaregistry.rest.SchemaRegistryRestApplication.initSchemaRegistry(SchemaRegistryRestApplication.java:66)
      at io.confluent.kafka.schemaregistry.rest.SchemaRegistryRestApplication.configureBaseApplication(SchemaRegistryRestApplication.java:81)
      at io.confluent.rest.Application.createServer(Application.java:205)
      at io.confluent.kafka.schemaregistry.rest.SchemaRegistryMain.main(SchemaRegistryMain.java:42)
  Caused by: io.confluent.kafka.schemaregistry.storage.exceptions.StoreInitializationException: Failed trying to create or validate schema topic configuration
      at io.confluent.kafka.schemaregistry.storage.KafkaStore.createOrVerifySchemaTopic(KafkaStore.java:179)
      at io.confluent.kafka.schemaregistry.storage.KafkaStore.init(KafkaStore.java:116)
      at io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.init(KafkaSchemaRegistry.java:222)
      ... 4 more
  Caused by: java.util.concurrent.ExecutionException: org.apache.kafka.common.errors.SslAuthenticationException: SSL handshake failed
      at org.apache.kafka.common.internals.KafkaFutureImpl.wrapAndThrow(KafkaFutureImpl.java:45)
      at org.apache.kafka.common.internals.KafkaFutureImpl.access$000(KafkaFutureImpl.java:32)
      at org.apache.kafka.common.internals.KafkaFutureImpl$SingleWaiter.await(KafkaFutureImpl.java:104)
      at org.apache.kafka.common.internals.KafkaFutureImpl.get(KafkaFutureImpl.java:272)
      at io.confluent.kafka.schemaregistry.storage.KafkaStore.createOrVerifySchemaTopic(KafkaStore.java:167)
      ... 6 more
  Caused by: org.apache.kafka.common.errors.SslAuthenticationException: SSL handshake failed
  Caused by: javax.net.ssl.SSLHandshakeException: General SSLEngine problem
      at sun.security.ssl.Handshaker.checkThrown(Handshaker.java:1521)
      at sun.security.ssl.SSLEngineImpl.checkTaskThrown(SSLEngineImpl.java:528)
      at sun.security.ssl.SSLEngineImpl.writeAppRecord(SSLEngineImpl.java:1197)
      at sun.security.ssl.SSLEngineImpl.wrap(SSLEngineImpl.java:1165)
      at javax.net.ssl.SSLEngine.wrap(SSLEngine.java:469)
      at org.apache.kafka.common.network.SslTransportLayer.handshakeWrap(SslTransportLayer.java:448)
      at org.apache.kafka.common.network.SslTransportLayer.doHandshake(SslTransportLayer.java:313)
      at org.apache.kafka.common.network.SslTransportLayer.handshake(SslTransportLayer.java:265)
      at org.apache.kafka.common.network.KafkaChannel.prepare(KafkaChannel.java:170)
      at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:547)
      at org.apache.kafka.common.network.Selector.poll(Selector.java:483)
      at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:539)
      at org.apache.kafka.clients.admin.KafkaAdminClient$AdminClientRunnable.run(KafkaAdminClient.java:1152)
      at java.lang.Thread.run(Thread.java:748)
  Caused by: javax.net.ssl.SSLHandshakeException: General SSLEngine problem
      at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
      at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1709)
      at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:318)
      at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310)
      at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1639)
      at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:223)
      at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037)
      at sun.security.ssl.Handshaker$1.run(Handshaker.java:970)
      at sun.security.ssl.Handshaker$1.run(Handshaker.java:967)
      at java.security.AccessController.doPrivileged(Native Method)
      at sun.security.ssl.Handshaker$DelegatedTask.run(Handshaker.java:1459)
      at org.apache.kafka.common.network.SslTransportLayer.runDelegatedTasks(SslTransportLayer.java:402)
      at org.apache.kafka.common.network.SslTransportLayer.handshakeUnwrap(SslTransportLayer.java:484)
      at org.apache.kafka.common.network.SslTransportLayer.doHandshake(SslTransportLayer.java:340)
      ... 7 more
  Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
      at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397)
      at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302)
      at sun.security.validator.Validator.validate(Validator.java:262)
      at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
      at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:281)
      at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:136)
      at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1626)
      ... 16 more
  Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
      at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
      at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
      at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
      at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392)
      ... 22 more
  </code></pre>
  
  <p><code>schema-registry.properties</code> configuration :</p>
  
  <pre><code>listeners=https://localhost:8081
  kafkastore.connection.url=localhost:2181
  kafkastore.bootstrap.servers=SSL://localhost:9092
  kafkastore.topic=_schemas
  kafkastore.topic.replication.factor=1
  kafkastore.security.protocol=SSL
  ssl.truststore.location=/.kafka_ssl/kafka.server.truststore.jks
  ssl.truststore.password=password
  ssl.keystore.location=/.kafka_ssl/kafka.server.keystore.jks
  ssl.keystore.password=password
  ssl.key.password=password
  ssl.endpoint.identification.algorithm=
  inter.instance.protocol=https
  </code></pre>
  
  <p>can someone advise ? </p>