hm. sorry, but did you "apply" after making changes? )inside the server configuration block, after the directives for the logs and error pages paths, the locations configuration blocks should begin: first built-in, and then added by you through the GUI
sorry, realy dont know what to say. other nginx.conf file is a template file at /usr/local/opnsense/service/templates/opnsense/nginx/ but its small and contains only modules and includesreal nginx config should be in /usr/local/etc/nginx/nginx.conf