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Fix Remotely Save WebDAV 451 Error on ASUS Router

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Fix Remotely Save WebDAV 451 Error on ASUS Router

You've set up Obsidian with the Remotely Save plugin and everything works fine on your home network. But the moment you leave home and try to sync over WebDAV, you get this:

Error: Invalid response: 451 Unavailable For Legal Reasons

If you're using an ASUS router with AiCloud and an asuscomm.com DDNS address, this guide is for you. The good news: the fix is straightforward once you know what's actually happening.

What's going on

The problem isn't your URL, username, or password.

When you access your router remotely via asuscomm.com, traffic doesn't go directly to your router — it gets routed through ASUS's relay servers first. These relay servers handle standard browser requests (GET) just fine, which is why the AiCloud web UI works in your browser.

The problem is that WebDAV uses non-standard HTTP methods that the relay blocks. When Remotely Save tries to sync, it sends requests like PROPFIND (to list files) and PUT (to upload). The ASUS relay sees these unfamiliar methods and returns 451.

[Remotely Save]
      ↓
[ASUS Relay Server]  ← blocks PROPFIND, PUT → returns 451
      ↓ (passes GET through fine)
[Your Router / AiCloud]

The fix? Bypass the relay entirely by connecting directly to your router via port forwarding.

The fix: port forwarding

Step 1: Set up port forwarding on your router

Log into your router admin panel and go to WAN → Virtual Server / Port Forwarding. Add a new rule:

| Field | Value | |---|---| | External Port | 10443 | | Internal IP | 192.168.50.1 (your router's own IP) | | Internal Port | 443 | | Protocol | TCP |

Important: the internal IP should point to the router itself, not a NAS or any other device.

Step 2: Update the Server Address in Remotely Save

Change your WebDAV server address to use the new port:

https://xxxx.asuscomm.com:10443/sda1/Obsidian/

Make sure the URL ends with a trailing slash — Remotely Save requires it.

Step 3: Verify the port is actually open

Before hitting Check Connectivity, confirm the port is reachable from the outside world. Head to yougetsignal.com/tools/open-ports and enter:

  • Host: xxxx.asuscomm.com
  • Port: 10443

You want to see Open. If it says Closed, double-check your port forwarding rule.

Step 4: Test in Remotely Save

Go back to Remotely Save settings and click Check Connectivity. You should see "The webdav server can be accessed."

Still not working? Try disabling TLS verification

ASUS routers use a self-signed SSL certificate. Remotely Save may reject it even after port forwarding. If the UI doesn't show a skipTlsVerify option, edit the config file directly.

File location:

YourVault/.obsidian/plugins/remotely-save/data.json

On Windows, .obsidian is a hidden folder — enable "Hidden items" in File Explorer's View menu.

Open the file in any text editor and find the webdav section. Add "skipTlsVerify": true:

"webdav": {
  "address": "https://xxxx.asuscomm.com:10443/sda1/Obsidian/",
  "username": "...",
  "password": "...",
  "authType": "basic",
  "skipTlsVerify": true
}

Save the file, then fully quit and restart Obsidian for the change to take effect.

Quick troubleshooting checklist

If you're still stuck, run through this list:

  • [ ] Server Address ends with /
  • [ ] Disk name (e.g. sda1) matches exactly what you see in AiCloud
  • [ ] The Obsidian folder actually exists in AiCloud (WebDAV won't create it automatically)
  • [ ] Port forwarding rule is saved and pointing to the router's own IP
  • [ ] Port shows as Open in an external port checker
  • [ ] skipTlsVerify: true set and Obsidian restarted

Why does 451 show up specifically?

HTTP 451 officially means "Unavailable For Legal Reasons" — a bit dramatic for what's happening here. In practice, ASUS's relay server uses this status code when it blocks a request it doesn't want to handle. It's a quirk of their implementation, not an actual legal issue with your setup.

Wrapping up

The 451 error in this context almost always comes down to one thing: ASUS's relay server blocking WebDAV traffic. No amount of tweaking your URL or credentials will fix it because the issue happens before the request even reaches your router.

Port forwarding bypasses the relay, lets Remotely Save talk directly to your router, and gets your Obsidian sync working everywhere.