[WARNING][2018-09-17 18:40:26] Exception during provisioning (from hudson.plugins.ec2.EC2Cloud provision)
com.amazonaws.SdkClientException: Unable to execute HTTP request: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleRetryableException(AmazonHttpClient.java:1116)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1066)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.doExecute(AmazonHttpClient.java:743)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeWithTimer(AmazonHttpClient.java:717)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.execute(AmazonHttpClient.java:699)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.access$500(AmazonHttpClient.java:667)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutionBuilderImpl.execute(AmazonHttpClient.java:649)
        at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:513)
        at com.amazonaws.services.ec2.AmazonEC2Client.doInvoke(AmazonEC2Client.java:16440)
        at com.amazonaws.services.ec2.AmazonEC2Client.invoke(AmazonEC2Client.java:16416)
        at com.amazonaws.services.ec2.AmazonEC2Client.executeDescribeInstances(AmazonEC2Client.java:8101)
        at com.amazonaws.services.ec2.AmazonEC2Client.describeInstances(AmazonEC2Client.java:8076)
        at com.amazonaws.services.ec2.AmazonEC2Client.describeInstances(AmazonEC2Client.java:8113)
        at hudson.plugins.ec2.EC2Cloud.countCurrentEC2Slaves(EC2Cloud.java:363)
        at hudson.plugins.ec2.EC2Cloud.getPossibleNewSlavesCount(EC2Cloud.java:502)
        at hudson.plugins.ec2.EC2Cloud.getNewOrExistingAvailableSlave(EC2Cloud.java:522)
        at hudson.plugins.ec2.EC2Cloud.provision(EC2Cloud.java:551)
        at hudson.slaves.NodeProvisioner$StandardStrategyImpl.apply(NodeProvisioner.java:715)
        at hudson.slaves.NodeProvisioner.update(NodeProvisioner.java:320)
        at hudson.slaves.NodeProvisioner.access$000(NodeProvisioner.java:61)
        at hudson.slaves.NodeProvisioner$NodeProvisionerInvoker.doRun(NodeProvisioner.java:809)
        at hudson.triggers.SafeTimerTask.run(SafeTimerTask.java:72)
        at jenkins.security.ImpersonatingScheduledExecutorService$1.run(ImpersonatingScheduledExecutorService.java:58)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: javax.net.ssl.SSLHandshakeException: 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.ssl.Alerts.getSSLException(Alerts.java:192)
        at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1964)
        at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:328)
        at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:322)
        at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1614)
        at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
        at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1052)
        at sun.security.ssl.Handshaker.process_record(Handshaker.java:987)
        at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1072)
        at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385)
        at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
        at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397)
        at org.apache.http.conn.ssl.SSLConnectionSocketFactory.createLayeredSocket(SSLConnectionSocketFactory.java:396)
        at org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket(SSLConnectionSocketFactory.java:355)
        at com.amazonaws.http.conn.ssl.SdkTLSSocketFactory.connectSocket(SdkTLSSocketFactory.java:142)
        at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142)
        at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:373)
        at sun.reflect.GeneratedMethodAccessor135.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at com.amazonaws.http.conn.ClientConnectionManagerFactory$Handler.invoke(ClientConnectionManagerFactory.java:76)
        at com.amazonaws.http.conn.$Proxy79.connect(Unknown Source)
        at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:381)
        at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:237)
        at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185)
        at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
        at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
        at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56)
        at com.amazonaws.http.apache.client.impl.SdkHttpClient.execute(SdkHttpClient.java:72)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeOneRequest(AmazonHttpClient.java:1238)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1058)
        ... 28 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:260)
        at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
        at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
        at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
        at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1596)
        ... 54 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)
        ... 60 more