Nginx 404 with fof/sitemap

[LittleSheep2Code]

Can I use the sitemap plugin with this?
I access it and get 404 error

My proxychain:
docker(LocalServer) -> Nginx(LocalServer) -> Frpc(LocalServer) -> Frps -> Nginx

My forum url: https://forum.smartsheep.club
I can sure the remote server configure is right, because I access it use the localhost and it is same 404 error
Any, question or suggest?

The description said I need change the nginx configure, and how I change it? I need add this things:

location = /sitemap.xml {
    try_files $uri $uri/ /index.php?$query_string;
}

Thanks.

[Magicalex]

https://github.com/mondediefr/docker-flarum#custom-vhost-flarum-nginx