I have Jenkins 2.84 version. While I add new plugin as Pipeline from localhost in Windows. I checked advanced tab in plugin manager, It has update site (http://updates.jenkins.io/update-center.json) then it shows this error "Signature verification failed in update site 'default' (show details)" And IF I update the site (https://updates.jenkins.io/update-center.json).  and while I click on Check Now button, It is showing "OOPS Error".I have Jenkins 2.84 version. While I add new plugin as Pipeline from localhost in Windows. I checked advanced tab in plugin manager, It has update site (http://updates.jenkins.io/update-center.json) then it shows this error "Signature verification failed in update site 'default' (show details)" And IF I update the site (https://updates.jenkins.io/update-center.json).  and while I click on Check Now button, It is showing "OOPS Error".
It shows "A problem occurred while processing the request. Please check our bug tracker to see if a similar problem has already been reported. If it is already reported, please vote and put a comment on it to let us gauge the impact of the problem. If you think this is a new issue, please file a new issue. When you file an issue, make sure to add the entire stack trace, along with the version of Jenkins and relevant plugins. The users list might be also useful in understanding what has happened.
Stack tracesun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.provider.certpath.SunCertPathBuilder.build(Unknown Source) at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(Unknown Source) at java.security.cert.CertPathBuilder.build(Unknown Source)Caused: sun.security.validator.ValidatorException: PKIX path building failed at sun.security.validator.PKIXValidator.doBuild(Unknown Source) at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) at sun.security.validator.Validator.validate(Unknown Source) at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source)Caused: javax.net.ssl.SSLHandshakeException at sun.security.ssl.Alerts.getSSLException(Unknown Source) at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source) at sun.security.ssl.Handshaker.fatalSE(Unknown Source) at sun.security.ssl.Handshaker.fatalSE(Unknown Source) at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source) at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source) at sun.security.ssl.Handshaker.processLoop(Unknown Source) at sun.security.ssl.Handshaker.process_record(Unknown Source) at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source) at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source) at hudson.model.DownloadService.loadJSON(DownloadService.java:167) at hudson.model.UpdateSite.updateDirectlyNow(UpdateSite.java:190) at hudson.PluginManager.doCheckUpdatesServer(PluginManager.java:1629) at java.lang.invoke.MethodHandle.invokeWithArguments(Unknown Source) at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:343) at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:52) at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26) at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:184) at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:117) at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:129) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:715) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:845) at org.kohsuke.stapler.MetaClass$2.doDispatch(MetaClass.java:186) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:715) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:845) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649) at org.kohsuke.stapler.Stapler.service(Stapler.java:238) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:841) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:135) at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:138) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:85) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84) at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249) at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:90) at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:190) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:188) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1253) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:168) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:166) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1155) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:564) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:317) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:110) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124) at org.eclipse.jetty.util.thread.Invocable.invokePreferred(Invocable.java:128) at org.eclipse.jetty.util.thread.Invocable$InvocableExecutor.invoke(Invocable.java:222) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:294) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:199) at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source)"