Last step of distribution wizard throws an error

2016-10-31 13:54:18,154 [XWiki Solr index job thread] INFO  o.x.s.s.i.j.IndexerJob         - Finished job of type [solr.indexer] with identifier [[solr, indexer]] 
2016-10-31 13:59:55,876 [Core extension repository updater] ERROR aultExtensionRepositoryManager - Unexpected error when trying to find extension [jdom:jdom-1.1.3] in repository [maven-xwikicom:maven:https://nexus.xwiki.com/nexus/content/repositories/public-store-releases/] 
org.xwiki.extension.ResolveException: Failed to resolve artifact [jdom:jdom:jar:1.1.3] descriptor
	at org.xwiki.extension.repository.aether.internal.AetherExtensionRepository.resolveMaven(AetherExtensionRepository.java:402)
	at org.xwiki.extension.repository.aether.internal.AetherExtensionRepository.resolveMaven(AetherExtensionRepository.java:385)
	at org.xwiki.extension.repository.aether.internal.AetherExtensionRepository.resolveMaven(AetherExtensionRepository.java:379)
	at org.xwiki.extension.repository.aether.internal.AetherExtensionRepository.resolve(AetherExtensionRepository.java:196)
	at org.xwiki.extension.repository.internal.DefaultExtensionRepositoryManager.resolve(DefaultExtensionRepositoryManager.java:288)
	at org.xwiki.extension.repository.internal.core.DefaultCoreExtensionScanner.updateExtensions(DefaultCoreExtensionScanner.java:213)
	at org.xwiki.extension.repository.internal.core.DefaultCoreExtensionRepository$1.run(DefaultCoreExtensionRepository.java:140)
	at java.lang.Thread.run(Thread.java:745)
Caused by: org.eclipse.aether.resolution.ArtifactResolutionException: Could not transfer artifact jdom:jdom:pom:1.1.3 from/to maven-xwikicom (https://nexus.xwiki.com/nexus/content/repositories/public-store-releases/): sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:444)
	at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifacts(DefaultArtifactResolver.java:246)
	at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifact(DefaultArtifactResolver.java:223)
	at org.xwiki.extension.repository.aether.internal.AetherExtensionRepository.loadPom(AetherExtensionRepository.java:513)
	at org.xwiki.extension.repository.aether.internal.AetherExtensionRepository.resolveMaven(AetherExtensionRepository.java:396)
	... 7 common frames omitted
Caused by: org.eclipse.aether.transfer.ArtifactTransferException: Could not transfer artifact jdom:jdom:pom:1.1.3 from/to maven-xwikicom (https://nexus.xwiki.com/nexus/content/repositories/public-store-releases/): sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at org.eclipse.aether.connector.basic.ArtifactTransportListener.transferFailed(ArtifactTransportListener.java:43)
	at org.eclipse.aether.connector.basic.BasicRepositoryConnector$TaskRunner.run(BasicRepositoryConnector.java:355)
	at org.eclipse.aether.util.concurrency.RunnableErrorForwarder$1.run(RunnableErrorForwarder.java:67)
	at org.eclipse.aether.connector.basic.BasicRepositoryConnector$DirectExecutor.execute(BasicRepositoryConnector.java:581)
	at org.eclipse.aether.connector.basic.BasicRepositoryConnector.get(BasicRepositoryConnector.java:249)
	at org.eclipse.aether.internal.impl.DefaultArtifactResolver.performDownloads(DefaultArtifactResolver.java:520)
	at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:421)
	... 11 common frames omitted
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:1949)
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302)
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296)
	at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1509)
	at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
	at sun.security.ssl.Handshaker.processLoop(Handshaker.java:979)
	at sun.security.ssl.Handshaker.process_record(Handshaker.java:914)
	at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1062)
	at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1375)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1403)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1387)
	at org.apache.http.conn.ssl.SSLSocketFactory.connectSocket(SSLSocketFactory.java:553)
	at org.apache.http.conn.ssl.SSLSocketFactory.connectSocket(SSLSocketFactory.java:412)
	at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:179)
	at org.apache.http.impl.conn.ManagedClientConnectionImpl.open(ManagedClientConnectionImpl.java:328)
	at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:612)
	at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:447)
	at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:884)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:71)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:55)
	at org.apache.http.impl.client.DecompressingHttpClient.execute(DecompressingHttpClient.java:164)
	at org.eclipse.aether.transport.http.HttpTransporter.execute(HttpTransporter.java:318)
	at org.eclipse.aether.transport.http.HttpTransporter.implGet(HttpTransporter.java:274)
	at org.eclipse.aether.spi.connector.transport.AbstractTransporter.get(AbstractTransporter.java:59)
	at org.eclipse.aether.connector.basic.BasicRepositoryConnector$GetTaskRunner.runTask(BasicRepositoryConnector.java:447)
	at org.eclipse.aether.connector.basic.BasicRepositoryConnector$TaskRunner.run(BasicRepositoryConnector.java:350)
	... 16 common frames omitted
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:387)
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:230)
	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:1491)
	... 38 common frames omitted
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:382)
	... 44 common frames omitted
2016-10-31 13:59:56,100 [Core extension repository updater] ERROR aultExtensionRepositoryManager - Unexpected error when trying to find extension [jdom:jdom-1.1.3] in repository [store.xwiki.com:xwiki:https://store.xwiki.com/xwiki/rest] 
org.xwiki.extension.ResolveException: Failed to create extension object for extension [jdom:jdom-1.1.3]
	at org.xwiki.extension.repository.xwiki.internal.XWikiExtensionRepository.resolve(XWikiExtensionRepository.java:340)
	at org.xwiki.extension.repository.internal.DefaultExtensionRepositoryManager.resolve(DefaultExtensionRepositoryManager.java:288)
	at org.xwiki.extension.repository.internal.core.DefaultCoreExtensionScanner.updateExtensions(DefaultCoreExtensionScanner.java:213)
	at org.xwiki.extension.repository.internal.core.DefaultCoreExtensionRepository$1.run(DefaultCoreExtensionRepository.java:140)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.IOException: Failed to request [https://store.xwiki.com/xwiki/rest/repository/extensions/jdom%3Ajdom/versions/1.1.3]
	at org.xwiki.extension.repository.xwiki.internal.XWikiExtensionRepository.getRESTResource(XWikiExtensionRepository.java:242)
	at org.xwiki.extension.repository.xwiki.internal.XWikiExtensionRepository.getRESTObject(XWikiExtensionRepository.java:300)
	at org.xwiki.extension.repository.xwiki.internal.XWikiExtensionRepository.resolve(XWikiExtensionRepository.java:335)
	... 4 common frames omitted
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:1949)
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302)
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296)
	at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1509)
	at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
	at sun.security.ssl.Handshaker.processLoop(Handshaker.java:979)
	at sun.security.ssl.Handshaker.process_record(Handshaker.java:914)
	at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1062)
	at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1375)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1403)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1387)
	at org.apache.http.conn.ssl.SSLConnectionSocketFactory.createLayeredSocket(SSLConnectionSocketFactory.java:394)
	at org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket(SSLConnectionSocketFactory.java:353)
	at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:141)
	at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:353)
	at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:380)
	at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
	at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:184)
	at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:88)
	at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
	at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:107)
	at org.xwiki.extension.repository.xwiki.internal.XWikiExtensionRepository.getRESTResource(XWikiExtensionRepository.java:239)
	... 6 common frames omitted
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:387)
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:230)
	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:1491)
	... 26 common frames omitted
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:382)
	... 32 common frames omitted