Can't get my Nextcloud AIO working with caddy reverse proxy (Docker)

[pascalriemer]

After successfully setting up Nextcloud AIO in reverse proxy mode, I'm unfortunately getting "The page isn’t redirecting properly" errors in Firefox, after trying for hours what ChatGPT 3o-mini-high suggests to me for troubleshooting.
I'm kind of a noob and running my homelab as a sidequest, I don't know how to proced here anymore.

Config.php:

'trusted_domains' => ['my.domain.com'],
'trusted_proxies' => ['172.29.8.7'],  // Container name if in same network
'overwriteprotocol' => 'https',
'overwrite.cli.url' => 'https://my.domain.com',
'overwritewebroot'   => '/',
'forwarded_for_headers' => ['HTTP_X_FORWARDED_FOR'],

My Docker compose:

services:
  nextcloud-aio-mastercontainer:
    image: nextcloud/all-in-one:latest
    container_name: nextcloud-aio-mastercontainer
    restart: always
    volumes:
      - nextcloud_aio_mastercontainer:/mnt/docker-aio-config
      - /var/run/docker.sock:/var/run/docker.sock:ro
    ports:
      - "8081:8080"  # AIO interface – use an available host port if needed
    environment:
      - APACHE_PORT=11000
      - APACHE_IP_BINDING=0.0.0.0
      - APACHE_ADDITIONAL_NETWORK=networking_app_net
      - SKIP_DOMAIN_VALIDATION=false
    networks:
      networking_app_net:
        aliases:
          - nextcloud

volumes:
  nextcloud_aio_mastercontainer:
    name: nextcloud_aio_mastercontainer

networks:
  networking_app_net:
     external: true

from caddy stack:

networks: # **CRITICAL: Define networks FIRST, before services**
  app_net:
    driver: bridge

volumes: # Define volumes next (good practice, though less critical than network order here)
  caddy_data:
    driver: local
    driver_opts:
      o: bind
      type: none
      device: /share/Media/config/caddy/data
  caddy_config:
    driver: local
    driver_opts:
      o: bind
      type: none
      device: /share/Media/config/caddy/config
  caddy:
    image: caddybuilds/caddy-cloudflare:latest
    container_name: caddy
    restart: unless-stopped
    ports:
      - "80:80"
      - "443:443"
      - "443:443/udp"
    volumes:
      - /share/Media/config/caddy/data:/data
      - /share/Media/config/caddy/config:/config
      - /share/Media/config/caddy/config/Caddyfile:/etc/caddy/Caddyfile
      - /share/Public/tailscale-certs:/etc/tailscale-certs:ro
    networks:
      - app_net
    environment:
      - [email protected] # **REPLACE WITH YOUR EMAIL!**
      - CLOUDFLARE_API_TOKEN={CLOUDFLARE_API_TOKEN}

Caddyfile:

my.domain.com {
  reverse_proxy http://nextcloud-aio-apache:11000 {
    header_up Host {host}
    header_up X-Forwarded-Proto "https"
    header_up X-Forwarded-Host {host}
    header_up X-Forwarded-For {remote_host}
  }
  tls {
    dns cloudflare {env.CLOUDFLARE_API_TOKEN}
  }
}

Nextcloud containers (master and apache) and caddy are in the same docker network. I did a curl to the nextcloud apache container and pasted the response into chatgpt, here the response:
The repeated redirect (308/302) usually means Nextcloud still isn’t “happy” with the URL it’s using—even though Caddy is terminating TLS correctly. In many cases, this is caused by Nextcloud’s overwrite settings.

I have Adguard home running as my local DNS server (all this runs on a QNAP NAS). DNS rewrite there is implemented. Cloudflare is set up.

I've also tried this, but the error didn't change:
#575 (comment)

Any help is really appreciated!

[szaimen]

Hi, can you follow https://github.com/nextcloud/all-in-one/blob/main/reverse-proxy.md#6-how-to-debug-things?

[pascalriemer]

Hi, I did that. Is there a step that you would explicitly recommend me to follow?

[szaimen]

For example did you open the aio interface at port 8081 and typed in your domain?

[pascalriemer]

Yes, of course I did. Thanks for our efforts, but I'd much prefer actually helpful answers.

[szaimen]

So what happens if you enter the domain? What error is shown?