nextcloudpi behind proxy works only with ip not with hostname

[dietrest]

I've created NPM and nextcloudpi with the following compose file:

 version: '3.8'

services:
  app:
    image: 'jc21/nginx-proxy-manager:latest'
    restart: unless-stopped
    ports:
      - '80:80'
      - '81:81'
      - '443:443'
    volumes:
      - ./data/resolv.conf:/etc/resolv.conf
      - ./data:/data
      - ./letsencrypt:/etc/letsencrypt
    networks:
      - proxy

  nextcloudpi:
    container_name: nextcloudpi
    image: ownyourbits/nextcloudpi
    restart: always
    volumes:
      - /srv/md0/nc-docker/resolv.conf:/etc/resolv.conf
      - /srv/md0/nc-docker:/data

    networks:
      - proxy

networks:
    proxy:
        external: true

the docker net proxy I've created to get always the same IP Rangeand and resolv.conf linked extern to edit it easyly. The Standard: nameserver 127.0.0.11 doesn't work, I need 172.25.0.1 for the net 172.25.0.0. Otherwise the Containers don' have Internet.
My Provider gave me a Audicodes500 that I have to use to let the Internet in. Everything else in my LAN is Connected to my Fritzbox 7590 that is connected to the Audiocodes. The fritzbox is configured as DMZ in the Audiocodes so that everything is foerwarded to the fritzbox.
the external hostname is obtained from duckdns.org.
my docker net proxy:
root@debian-server:/srv/md0/nc-nginx-proxy# docker network inspect proxy
[
{
"Name": "proxy",
"Id": "dd0645555d27c6d0d738a86ceb690c01473779eccdeddc7a537532414bc7aa42",
"Created": "2023-08-27T17:55:16.106469637+02:00",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": {},
"Config": [
{
"Subnet": "172.25.0.0/16",
"Gateway": "172.25.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"cfaf8140d7464d5cbb61d46b4bc4b193b39e2c4a9cc189a12e59c98a69074a31": {
"Name": "nc-nginx-proxy-app-1",
"EndpointID": "2ace49efdce2c4d01086e7ab637e7424ef3a35fdfd64db095b87933cf7a4be70",
"MacAddress": "02:42:ac:19:00:03",
"IPv4Address": "172.25.0.3/16",
"IPv6Address": ""
},
"d86dad56fbddd8a307fdf88f15ded130aed6fbd55fd9245a83925021e40dd2df": {
"Name": "nextcloudpi",
"EndpointID": "9d9940387f8a76d33e83f1144ddae7e2f97f991ca0d68d44e2c55774eb8a69ab",
"MacAddress": "02:42:ac:19:00:02",
"IPv4Address": "172.25.0.2/16",
"IPv6Address": ""
}
},
"Options": {},
"Labels": {}
}
]

With this created proxy host the nextcloud works, but if I change the IP to the Hostname "nextcloudpi"
I get a 502 error.

[lastsamurai26]

You need to check what the real hostname is from the Docker

normally you can start the docker with hostname: ;) maybe this helps

[backupandforkacc]

I used to use nextcloudpi in the past, but now I just use zfs, make screenshots and use nextcloud in docker.
With nextcloud, it works properly:

[lastsamurai26]

you are using the nextcloud official AIO nextcloud or a third docker nextcloud ?

[backupandforkacc]

I am using this one:
https://hub.docker.com/_/nextcloud/

If there is a way to migrate to AIO, that would also be nice.

[lastsamurai26]

Unfortunately, I have to admit that I also use them and make my own backups.

didn't find a way to migrate to the AIO but the Nginx Proxy Manager needs to be run as host mode
The AIO has everything integrated but also kind of hard to configure in terms of proxy etc..