I have completely removed Nginx to update to the official Nginx stable version (nginx/1.8.1 instead of the old one in standard ubuntu). Then I reinstalled Nginx, put all the config files back in "/etc/nginx/sites-enabled/". All my sites are working. ISPconfig 3 is not working, but I think I know why: It has a .conf file in another folder, but I don't have an idea in which folder it is. Please note that I have a full server backup, so I have all config files and other files before I removed Nginx. My configuration: - Ubuntu 14.04 (trusty) - ISPConfig version 22.214.171.124p8 Anyone an idea how I make ISPconfig 3 active again in Nginx?