ControllersGrailsPlugin is generating mappings for all error codes (400..417 + 500..505) when it should only map error codes specified in the UrlMappings file. This is resulting in the swallowing of error-codes that are needed downstream by the container and by clients. A fix for this should fix issue#1778 since the 401 (and 403) error-code mappings (to the ErrorHandlingServlet where they are swallowed) prevent container manager security. http://www.nabble.com/-Error-401--problem-getting-container-managed-security-working-with-Grails-Jetty-tf4734557.html#a13757709