docker-elk: SSL Problem PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed

Problem description

Following the instructions on the readme. After calling docker-compose exec -T elasticsearch bin/init_sg.sh

The following error was returned

Search Guard Admin v6
Will connect to localhost:9300 ... done
Unable to check whether cluster is sane: None of the configured nodes are available: [{#transport#-1}{Id9W9LEKRT2fD9qCPuzysQ}{localhost}{127.0.0.1:9300}]
08:22:56.477 [elasticsearch[_client_][transport_client_boss][T#1]] ERROR com.floragunn.searchguard.ssl.transport.SearchGuardSSLNettyTransport - SSL Problem PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed
javax.net.ssl.SSLHandshakeException: PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed
	at sun.security.ssl.Alert.createSSLException(Alert.java:128) ~[?:?]
	at sun.security.ssl.TransportContext.fatal(TransportContext.java:321) ~[?:?]
	at sun.security.ssl.TransportContext.fatal(TransportContext.java:264) ~[?:?]
	at sun.security.ssl.TransportContext.fatal(TransportContext.java:259) ~[?:?]
	at sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1329) ~[?:?]
	at sun.security.ssl.CertificateMessage$T13CertificateConsumer.onConsumeCertificate(CertificateMessage.java:1204) ~[?:?]
	at sun.security.ssl.CertificateMessage$T13CertificateConsumer.consume(CertificateMessage.java:1151) ~[?:?]
	at sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:392) ~[?:?]
	at sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:444) ~[?:?]
	at sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1065) ~[?:?]
	at sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1052) ~[?:?]
	at java.security.AccessController.doPrivileged(Native Method) ~[?:?]
	at sun.security.ssl.SSLEngineImpl$DelegatedTask.run(SSLEngineImpl.java:999) ~[?:?]
	at io.netty.handler.ssl.SslHandler.runDelegatedTasks(SslHandler.java:1457) ~[netty-handler-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1365) ~[netty-handler-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1199) ~[netty-handler-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1243) ~[netty-handler-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:502) ~[netty-codec-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:441) ~[netty-codec-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:278) ~[netty-codec-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:644) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:579) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:496) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:458) [netty-transport-4.1.30.Final.jar:4.1.30.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:897) [netty-common-4.1.30.Final.jar:4.1.30.Final]
	at java.lang.Thread.run(Thread.java:834) [?:?]
Caused by: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed
	at sun.security.validator.PKIXValidator.doValidate(PKIXValidator.java:350) ~[?:?]
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:259) ~[?:?]
	at sun.security.validator.Validator.validate(Validator.java:264) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:321) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:279) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:141) ~[?:?]
	at sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1307) ~[?:?]
	... 29 more
Caused by: java.security.cert.CertPathValidatorException: validity check failed
	at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(PKIXMasterCertPathValidator.java:135) ~[?:?]
	at sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:233) ~[?:?]
	at sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:141) ~[?:?]
	at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(PKIXCertPathValidator.java:80) ~[?:?]
	at java.security.cert.CertPathValidator.validate(CertPathValidator.java:309) ~[?:?]
	at sun.security.validator.PKIXValidator.doValidate(PKIXValidator.java:345) ~[?:?]
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:259) ~[?:?]
	at sun.security.validator.Validator.validate(Validator.java:264) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:321) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:279) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:141) ~[?:?]
	at sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1307) ~[?:?]
	... 29 more
Caused by: java.security.cert.CertificateExpiredException: NotAfter: Tue Jan 15 20:48:52 UTC 2019
	at sun.security.x509.CertificateValidity.valid(CertificateValidity.java:274) ~[?:?]
	at sun.security.x509.X509CertImpl.checkValidity(X509CertImpl.java:687) ~[?:?]
	at sun.security.provider.certpath.BasicChecker.verifyValidity(BasicChecker.java:190) ~[?:?]
	at sun.security.provider.certpath.BasicChecker.check(BasicChecker.java:144) ~[?:?]
	at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(PKIXMasterCertPathValidator.java:125) ~[?:?]
	at sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:233) ~[?:?]
	at sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:141) ~[?:?]
	at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(PKIXCertPathValidator.java:80) ~[?:?]
	at java.security.cert.CertPathValidator.validate(CertPathValidator.java:309) ~[?:?]
	at sun.security.validator.PKIXValidator.doValidate(PKIXValidator.java:345) ~[?:?]
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:259) ~[?:?]
	at sun.security.validator.Validator.validate(Validator.java:264) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:321) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:279) ~[?:?]
	at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:141) ~[?:?]
	at sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1307) ~[?:?]
	... 29 more
ERR: Cannot connect to Elasticsearch. Please refer to elasticsearch logfile for more information
Trace:
NoNodeAvailableException[None of the configured nodes are available: [{#transport#-1}{Id9W9LEKRT2fD9qCPuzysQ}{localhost}{127.0.0.1:9300}]]
	at org.elasticsearch.client.transport.TransportClientNodesService.ensureNodesAreAvailable(TransportClientNodesService.java:349)
	at org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:247)
	at org.elasticsearch.client.transport.TransportProxyClient.execute(TransportProxyClient.java:60)
	at org.elasticsearch.client.transport.TransportClient.doExecute(TransportClient.java:382)
	at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:395)
	at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:384)
	at com.floragunn.searchguard.tools.SearchGuardAdmin.main0(SearchGuardAdmin.java:454)
	at com.floragunn.searchguard.tools.SearchGuardAdmin.main(SearchGuardAdmin.java:123)

The error happened 2nd time I brought up the cluster. First time calling docker-compose up and init sg actually works. But no code changes in between. Error seems to suggest something wrong with the key. Does the key in the config have an expiry dare? Could you shine some light on this? Thanks.