This week's book giveaway is in the Reactive Progamming forum. We're giving away four copies of Reactive Streams in Java: Concurrency with RxJava, Reactor, and Akka Streams and have Adam Davis on-line! See this thread for details.
A full stack trace would typically start out with something like
org.springframework.security.access.AccessDeniedException: Access is denied
I assume it is an access denied exception. If you are not seeing that make sure your log is not getting truncated. If you are using STS right click in the console and go to preferences, there unclick the limit console output checkbox.
Have you tried setting a break point in your handle(...) method? You should be hitting it.
One possibility if you are hitting that breakpoint is that you have forgotten to set intercept URL's for your /securityAccessDenied. This would cause another exception to get thrown.