/swagger-ui/index.html not found - nginx

Question

I follow here to setup separated front-end and back-end in centos 7 (with docker), using nginx to host my front-end, my website works, and all /api/.... requests work, however, when I want to check RESTful API serviced by swagger, got a 404 error, fiddler says:
not found /swagger-ui/index.html
I open 8080 on host and navigate the swagger-ui folder and index.html is just there. and all www folder is given 755 permission.
The nginx site.conf is as below:
server {
listen 80;
index index.html;
server_name localhost;
error_log /var/log/nginx/error.log;
location / {
root /usr/share/nginx/html;
}
location /api {
proxy_pass http://www.example.com:8080/api;
}
location /management {
proxy_pass http://www.example.com:8080/management;
}
location /v2 {
proxy_pass http://www.example.com:8080/v2;
}
location /swagger-ui {
proxy_pass http://www.example.com:8080/swagger-ui;
}
location /swagger-resources {
proxy_pass http://www.example.com:8080/swagger-resources;
}
}
What's wrong?
===============================updated
after issue:
sudo docker logs -f -t --tail 100 docker_nginx_1
found somethings wrong in log file:
2018-07-14T17:35:40.904857522Z 187.67.50.246 - - [14/Jul/2018:17:35:40 +0000] "GET /cgi/common.cgi HTTP/1.1" 404 169 "-" "Wget(linux)" "-"
2018-07-14T17:35:40.904920067Z 2018/07/14 17:35:40 [error] 5#5: *23 open() "/usr/share/nginx/html/cgi/common.cgi" failed (2: No such file or directory), client:187.67.50.246, server: localhost, request: "GET /cgi/common.cgi HTTP/1.1", host: "39.107.246.223"
2018-07-14T17:35:43.896984659Z 187.67.50.246 - - [14/Jul/2018:17:35:43 +0000] "GET /stssys.htm HTTP/1.1" 404 169 "-" "Wget(linux)" "-"

Answer 1

It works after I comment out:
location /swagger-ui {
proxy_pass http://www.example.com:8080/swagger-ui;
}
I thought swagger-ui was served by nginx instead of back-end.