After configuring Kerberos on the host and making sure it works, we created the keytab file and used kinit -k -t to test it against AD. All worked.

After saving the configuration, Jenkins drops the following.

Then, tried to remove the plugin and install it again, we are receiving this error again.

How can we wipe the plugin configuration so to start again?

Stack trace

java.lang.NullPointerException
    at org.codelibs.spnego.SpnegoAuthenticator.doSpnegoAuth(SpnegoAuthenticator.java:462)
    at org.codelibs.spnego.SpnegoAuthenticator.authenticate(SpnegoAuthenticator.java:281)
    at com.sonymobile.jenkins.plugins.kerberossso.ioc.SpnegoKerberosAuthenticationFactory$SpnegoKerberosAuthenticator.authenticate(SpnegoKerberosAuthenticationFactory.java:89)
    at com.sonymobile.jenkins.plugins.kerberossso.KerberosSSOFilter.doFilter(KerberosSSOFilter.java:182)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at org.jenkinsci.plugins.ssegateway.Endpoint$SSEListenChannelFilter.doFilter(Endpoint.java:225)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at io.jenkins.blueocean.ResourceCacheControl.doFilter(ResourceCacheControl.java:134)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at io.jenkins.blueocean.auth.jwt.impl.JwtAuthenticationFilter.doFilter(JwtAuthenticationFilter.java:51)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at com.smartcodeltd.jenkinsci.plugin.assetbundler.filters.LessCSS.doFilter(LessCSS.java:47)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at javax.servlet.FilterChain$doFilter.call(Unknown Source)
    at com.ceilfors.jenkins.plugins.jiratrigger.ExceptionLoggingFilter.doFilter(ExceptionLoggingFilter.groovy:29)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:125)
    at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
    at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:138)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
    at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:49)
    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:92)
    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$1.run(BoundedExecutorService.java:77)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:748)