Domain is not reachable despite (I think) being reachable

The Basics

  • Nextcloud Server version (e.g., 29.x.x):
    • N/A
  • Operating system and version (e.g., Ubuntu 24.04):
    • CachyOS
  • Web server and version (e.g, Apache 2.4.25):
    • N/A
  • Reverse proxy and version _(e.g. nginx 1.27.2)
    • Nginx Proxy Manager v2.12.3
  • PHP version (e.g, 8.3):
    • N/A
  • Is this the first time you’ve seen this error? (Yes / No):
    • Yes
  • When did this problem seem to first start?
    • During AIO first setup
  • Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
    • AIO
  • Are you using CloudfIare, mod_security, or similar? (Yes / No)
    • No

Summary of the issue you are facing:

I’m running a local server on local IP 10.0.2.4 with Nginx Proxy Manager and trying to install AIO on it. I have registered my domain with a registrar and pointing at my public IP, but I also have a local DNS server where the domain has an A record pointing to 10.0.2.4.

When I connect to nextcloud.<my domain>.net it successfully connects to the AIO setup screen, with SSL enabled (LetsEncrypt, via Nginx Proxy Manager)

But still, I get the error:

The domain is not reachable on Port 443 from within this container. Have you opened port 443/tcp in your router/firewall? If yes is the problem most likely that the router or firewall forbids local access to your domain. You can work around that by setting up a local DNS-server.

My (relevant) docker images:

CONTAINER ID   IMAGE                                               COMMAND                  CREATED          STATUS                    PORTS                                                                                                                                                                                            NAMES
88d3bb0ec998   ghcr.io/nextcloud-releases/aio-domaincheck:latest   "/start.sh"              17 minutes ago   Up 17 minutes (healthy)   0.0.0.0:11000->11000/tcp                                                                                                                                                                         nextcloud-aio-domaincheck
1a0387485647   ghcr.io/nextcloud-releases/all-in-one:latest        "/start.sh"              36 minutes ago   Up 36 minutes (healthy)   80/tcp, 8443/tcp, 9000/tcp, 0.0.0.0:4080->8080/tcp, [::]:4080->8080/tcp                                                                                                                          nextcloud-aio-mastercontainer
(...)
82249bc5f399   technitium/dns-server:latest                        "/usr/bin/dotnet /op…"   3 days ago       Up 3 days                 80/tcp, 67/udp, 443/tcp, 443/udp, 0.0.0.0:53->53/tcp, [::]:53->53/tcp, 853/tcp, 8053/tcp, 0.0.0.0:5380->5380/tcp, 0.0.0.0:53->53/udp, [::]:5380->5380/tcp, [::]:53->53/udp, 853/udp, 53443/tcp   dns-server
6ea8642ed94d   jc21/nginx-proxy-manager:latest                     "/init"                  3 days ago       Up 3 days                 0.0.0.0:80-81->80-81/tcp, [::]:80-81->80-81/tcp, 0.0.0.0:443->443/tcp, [::]:443->443/tcp                                                                                                         nginx_reverse_proxy-app-1

Steps to replicate it:

  1. Run AIO
  2. Type in the domain name

Log entries

Nextcloud

N/A

Web Browser

If the problem is related to the Web interface, open your browser inspector Console and Network tabs while refreshing (reloading) and reproducing the problem. Provide any relevant output/errors here that appear.

containers-form-submit.js?v4:4 Uncaught TypeError: Cannot read properties of null (reading 'style')
    at HTMLDocument.<anonymous> (containers-form-submit.js?v4:4:23)
(anonymous)	@	containers-form-submit.js?v4:4
forms.js:68 
 POST https://nextcloud.<my domain>.net/api/configuration 422 (Unprocessable Entity)
submit	@	forms.js:68

Web server / Reverse Proxy

nginx reverse proxy logs/proxy-host-7_error.log

2025/06/23 06:26:26 [error] 549#549: *73570 connect() failed (111: Connection refused) while connecting to upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "POST /api/configuration HTTP/1.1", upstream: "https://10.0.2.4:4080/api/configuration", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:26:26 [error] 549#549: *73570 connect() failed (111: Connection refused) while connecting to upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /containers HTTP/1.1", upstream: "https://10.0.2.4:4080/containers", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:26:26 [error] 549#549: *73570 connect() failed (111: Connection refused) while connecting to upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /favicon.ico HTTP/1.1", upstream: "https://10.0.2.4:4080/favicon.ico", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:26:27 [error] 549#549: *73570 peer closed connection in SSL handshake (104: Connection reset by peer) while SSL handshaking to upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /containers HTTP/1.1", upstream: "https://10.0.2.4:4080/containers", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:26:27 [error] 549#549: *73570 peer closed connection in SSL handshake (104: Connection reset by peer) while SSL handshaking to upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /favicon.ico HTTP/1.1", upstream: "https://10.0.2.4:4080/favicon.ico", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:26:59 [error] 549#549: *73570 peer closed connection in SSL handshake (104: Connection reset by peer) while SSL handshaking to upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /containers HTTP/1.1", upstream: "https://10.0.2.4:4080/containers", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:26:59 [error] 549#549: *73570 peer closed connection in SSL handshake while SSL handshaking to upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /favicon.ico HTTP/1.1", upstream: "https://10.0.2.4:4080/favicon.ico", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:27:04 [error] 549#549: *73589 upstream prematurely closed connection while reading response header from upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /containers HTTP/1.1", upstream: "https://10.0.2.4:4080/containers", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:29:55 [error] 596#596: *73627 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "POST /api/docker/start HTTP/1.1", upstream: "https://10.0.2.4:4080/api/docker/start", host: "nextcloud.<my domain>.net", referrer: "http://nextcloud.<my domain>.net/containers"
2025/06/23 06:40:02 [error] 596#596: *73960 upstream prematurely closed connection while reading response header from upstream, client: 10.0.1.252, server: nextcloud.<my domain>.net, request: "GET /containers HTTP/1.1", upstream: "https://10.0.2.4:4080/containers", host: "nextcloud.<my domain>.net", referrer: "http://proxy.<my domain>.net/"

If you would like more logs please let me know which logs/files.

Configuration

Nextcloud

N/A

Apps

N/A

1 Like

Hi, you might also need to adjust the docker daemon via daemon.json to use the local dns server. See Configuring DNS | dockerlabs

1 Like

That was the issue, thank you!

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