How to setup content range in NGINX?

I use django framework and I try to setup NGINX that server play video in browser chunk by chunk.

nginx.conf

proxy_cache_path /tmp/mycache keys_zone=mycache:100m;
server {
            listen 80;
            server_name localhost;

                proxy_cache mycache;
                slice              1m;
                proxy_cache_key    $host$uri$is_args$args$slice_range;
                proxy_set_header   Range $slice_range;
                proxy_http_version 1.1;
                proxy_cache_valid  200 206 1h;


            location / {
                include proxy_params;
                proxy_pass http://unix:/run/gunicorn.sock;
                       }


            location /vid/ {
                alias /home/affil/videos/;
               }
}

When I try locally

127.0.0.1/vid/test.mp4

, the video starts in browser as partial (206). Fast load.

When I try

http://[my_server_external_ip]/vid/test.mp4

, content range disappear and video starts playing after long time preload.

What's wrong with settings?