on the server host myserverhostname correctly resolves, but if I enter the container (docker exec -it nginx-app-1 bash) it does not work anymore:

[root@docker-11e3869f946f:/app]# host tserver
Host tserver not found: 3(NXDOMAIN)

(I had to install dnsutils before)

it seems a nginx issue then

here's the configuration file for jellyfin:

# ------------------------------------------------------------
# jellyfin.tubbadu.duckdns.org
# ------------------------------------------------------------



map $scheme $hsts_header {
https   "max-age=63072000; preload";
}

server {
set $forward_scheme http;
set $server         "192.168.1.13";
set $port           8096;

listen 80;
listen [::]:80;

listen 443 ssl;
listen [::]:443 ssl;


server_name jellyfin.tubbadu.duckdns.org;


# Let's Encrypt SSL
include conf.d/include/letsencrypt-acme-challenge.conf;
include conf.d/include/ssl-ciphers.conf;
ssl_certificate /etc/letsencrypt/live/npm-18/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/npm-18/privkey.pem;






# Block Exploits
include conf.d/include/block-exploits.conf;








proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $http_connection;
proxy_http_version 1.1;


access_log /data/logs/proxy-host-5_access.log proxy;
error_log /data/logs/proxy-host-5_error.log warn;







location / {








proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $http_connection;
proxy_http_version 1.1;


# Proxy!
include conf.d/include/proxy.conf;
}


# Custom
include /data/nginx/custom/server_proxy[.]conf;
}