Use $request_filename instead of $document_root$fastcgi_script_name as described in: https://www.nginx.com/resources/wiki/start/topics/tutorials/config_pitfalls/#use-request-filename-for-script-filename
Use $request_filename instead of $document_root$fastcgi_script_name as described in: https://www.nginx.com/resources/wiki/start/topics/tutorials/config_pitfalls/#use-request-filename-for-script-filename