I'd like trying to update Customer HTML on the administration page, but unfortunately after that the adiministration function(page) is invalid anymore. Left side UI menus missing, Sites management, User management, Add-on submenu are all invalid too. These pages show nothing(empty). Except administration, other functions(use sides) are still work well. What is the issue and how to recovery? My confluence version is V5.1.1 and using HSQL database(where db-files located). Any help would greatly appreciated.