RStudio server https port

RStudio IDE
1

Hello,
I'm using an rstudio server running in a VM behind a reverse proxy.

My nginx reverse proxy listen on port 9443 (i cannot use 443...), then i redirect request to the VM behind the proxy:

server {
    listen 9443 ssl http2;

    server_name        MY.FRONTEND.SERVER;
    ssl_certificate     /etc/nginx/ssl/certr.crt;
    ssl_certificate_key /etc/nginx/ssl/key.key;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_session_timeout 1d;
    ssl_session_cache shared:SSL:50m;
    ssl_stapling on;
    ssl_stapling_verify on;
    add_header Strict-Transport-Security max-age=15768000;

    location / {

        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        proxy_pass http://192.168.171.20:8787/;
        proxy_redirect http://192.168.171.20:8787/ $scheme://$host/;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_read_timeout 20d;

        client_max_body_size 20240M;
    }
}

but when i go to https://MY.FRONTEND.SERVER:9443/ i got a redirect to https://MY.FRONTEND.SERVER/hub/auth-sign-in?appUri=%2F

how can I configure to redirect to 9443 port, the SSL port available from outside ?

Thanks,
Igor