Getting this error on wildfly 20 version when we try to logout. 
it's not easy to reproduce, it's very sporadic. 

Caused by: javax.management.InstanceNotFoundException: jboss.as:subsystem=security,security-domain=ptsmc 69 at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getMBean(DefaultMBeanServerInterceptor.java:1083) 70 at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:806) 71 at java.management/com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)

 Code to flushoutlogin is 

private static void flushAuthenticationCache(final String userid) {

final String domain = "ptsmc-request";
try

{ ObjectName jaasMgr = new ObjectName("jboss.as:subsystem=security,security-domain=" + domain); Object[] params = \{ userid }

;
String[] signature = { "java.lang.String" };
MBeanServer server = MBeanServerFactory.findMBeanServer(null).get(0);
server.invoke(jaasMgr, "flushCache", params, signature);
} catch(Throwable e)

{ Throwables.propagate(e); }

}

 

We've application deployed on EC2 instance of AWS and can't find any relevant on localhost:9990 either. 
kindly help what is cause of this?