Can’t Access Nextcloud AIO via Port 8443 (ERR_SSL_PROTOCOL_ERROR), Internal Setup Only

ℹ️ Support
, ,
1

Hello everyone,

I’m running Nextcloud All-in-One (AIO) on a Windows 10/11 PC using Docker Desktop. I only want to access Nextcloud internally (no external port forwarding), but I’m having trouble getting HTTPS (port 8443) to work. Below is my setup and the problem details:

[Internet] (Public IP: 106.243.xxx.xx)
      |
      | 
      v
┌───────────────────────────┐
│  [Fiber Modem + NAT]      │   <-- Public IP assigned (106.243.xxx.xx)
│  WAN IP: 106.243.xxx.xx   │
│  LAN Range: 192.168.1.x   │
└───────────────────────────┘
           |
           | (LAN: 192.168.1.x)
           v
┌───────────────────────────┐
│  [Wi-Fi Router]           │   <-- WAN IP: 192.168.1.10 (private)
│  WAN: 192.168.1.10        │
│  LAN: 192.168.0.x         │
└───────────────────────────┘
           |
           | (LAN: 192.168.0.x)
           v
┌───────────────────────────┐
│  [Windows PC + Docker]    │
│  Internal IP: 192.168.0.xx
│  Nextcloud AIO (port 8443)
└───────────────────────────┘

  • The PC running Docker Desktop has IP 192.168.0.xx.

  • I’m using Nextcloud AIO. My Docker run command is (PowerShell syntax):

docker run ^
  --init ^
  --sig-proxy=false ^
  --name nextcloud-aio-mastercontainer ^
  --restart always ^
  --publish 80:80 ^
  --publish 8080:8080 ^
  --publish 8443:8443 ^
  --volume nextcloud_aio_mastercontainer:/mnt/docker-aio-config ^
  --volume //var/run/docker.sock:/var/run/docker.sock:ro ^
  nextcloud/all-in-one:latest

2. Goal

  • I only want internal access, so external port forwarding isn’t essential.
  • I tried using -e SKIP_DOMAIN_VALIDATION=true so that I don’t need a real domain.
  • I set a fake domain like nextcloud.local in the wizard, but I mostly just want to access Nextcloud via https://192.168.0.xx:8443.

Even though the logs say “Initial startup of Nextcloud All-in-One complete!” and everything seems to be running:

Initial startup of Nextcloud All-in-One complete!
You should be able to open the Nextcloud AIO Interface now on port 8080 of this server!

Port 8080 (the AIO interface) works and shows the setup screen.

But if I try https://192.168.0.xx:8443, I get:

This site can’t provide a secure connection
ERR_SSL_PROTOCOL_ERROR
  • I can see the AIO interface on port 8080, but I never get the actual Nextcloud login page on 8443.
  • I tried adding an inbound rule for 8443 in Windows Defender Firewall, and LG U+ (my ISP) says port 8443 isn’t blocked.
  • For now, I just want my internal LAN users to access Nextcloud. Even if 8443 is “self-signed” or something, I’d expect a certificate warning, not a protocol error.

What I’ve Tried

  1. SKIP_DOMAIN_VALIDATION – Let me skip domain checks, but still no 8443 success.
  2. hosts file – Mapped 192.168.0.xx nextcloud.local, can ping nextcloud.local, but still get ERR_SSL_PROTOCOL_ERROR on https://nextcloud.local:8443.
  3. Checking logs – The container logs look normal, with no obvious SSL errors.
  4. Disabling Windows Firewall – Same issue.
  5. Tried connecting via HTTP (http://192.168.0.xx:8443) – Of course, that fails since it expects HTTPS.

Additionally, if anyone knows of any recommended sites or tutorials on how to install Nextcloud using Docker Desktop, I would greatly appreciate it if you could share them.

2

Hi, see all-in-one/local-instance.md at main · nextcloud/all-in-one · GitHub