Stack trace 
java.lang.NoClassDefFoundError: Could not initialize class org.kohsuke.github.GitHub
	at org.kohsuke.github.GitHubBuilder.build(GitHubBuilder.java:207)
	at org.jenkinsci.plugins.GithubAuthenticationToken.getGitHub(GithubAuthenticationToken.java:302)
	at org.jenkinsci.plugins.GithubAuthenticationToken.loadMyself(GithubAuthenticationToken.java:486)
	at org.jenkinsci.plugins.GithubAuthenticationToken.<init>(GithubAuthenticationToken.java:199)
	at org.jenkinsci.plugins.GithubSecurityRealm.doFinishLogin(GithubSecurityRealm.java:405)
	at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
	at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:396)
	at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:408)
	at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:212)
	at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:145)
	at org.kohsuke.stapler.MetaClass$11.doDispatch(MetaClass.java:535)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:747)
Caused: javax.servlet.ServletException
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:797)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:878)
	at org.kohsuke.stapler.MetaClass$2.doDispatch(MetaClass.java:219)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:747)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:878)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:676)
	at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:154)
	at hudson.plugins.locale.LocaleFilter.doFilter(LocaleFilter.java:42)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
	at jenkins.telemetry.impl.UserLanguages$AcceptLanguageFilter.doFilter(UserLanguages.java:128)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
	at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:157)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:105)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	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:135)
	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.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:595)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)