Notes app: "The document could not be loaded. Please check your internet connection" even without reverse proxy

[cs224]

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The Basics

• Nextcloud Server version (e.g., 29.x.x):
  • 32.0.1
• Operating system and version (e.g., Ubuntu 24.04):
  • Debian GNU/Linux 13.1 (trixie)
• Web server and version (e.g, Apache 2.4.25):
  • nextcloud/all-in-one:beta
• Reverse proxy and version _(e.g. nginx 1.27.2)
  • Traefik 3.5.3
• PHP version (e.g, 8.3):
  • nextcloud/all-in-one:beta
• Is this the first time you’ve seen this error? (Yes / No):
  • Yes
• When did this problem seem to first start?
  • 2 weeks ago
• 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:

Hi everyone,

I’m running Nextcloud AIO (nextcloud/all-in-one:beta; version 32.0.1) on a home server, normally behind a Traefik reverse proxy that sits on a VPS.
On that same home server I recently installed Mailu, also behind Traefik.

Since adding Mailu, the Nextcloud Notes app in the web UI frequently shows: “The document could not be loaded. Please check your internet connection. Reconnect”
This did not happen before I made those changes.

At first I assumed this was a performance issue with my rather weak home server, so I upgraded the home server to a much more powerful machine. Unfortunately, the problem did not go away.

To rule out Traefik and the VPS path, I:

• Accessed Nextcloud directly on the AIO Apache port using http://localhost:11000/... (via SSH on the home server), completely bypassing Traefik/Mailu.
• I can reproduce the same Notes error there as well.
• I checked both the Network tab and the JavaScript console in the browser’s DevTools while the error occurs and don’t see anything suspicious (requests are 200/304, no obvious JS errors).

So at this point it looks like the issue is with AIO/Nextcloud/Notes itself, not in Traefik or Mailu.

Could you please:

• Suggest what to check next to get closer to the root cause (logs, configs, specific modules to look for, known Notes issues, etc.)?
• Let me know if this matches any known bugs with the Notes app and which logs or additional info would be most helpful to share?

Thanks a lot in advance for any hints or debugging ideas!

[jtr]

What do your Traefik logs indicate during these events?

The error itself comes from the Text app when is syncing (trying to connect to its backend on the server).

From what I can tell, the triggers would be things like HTTP 403/404/502/503/500 codes or outright connectivity loss. The URLs to look for would be something like /apps/text/*/*/sync.

Perhaps post your Compose file + Traefik config.

Accessed Nextcloud directly on the AIO Apache port using http://localhost:11000/... (via SSH on the home server), completely bypassing Traefik/Mailu.

Can you elaborate on your test method here? I don’t see how you’d test this way without also re-configuring Nextcloud itself (i.e. it would still use the embedded https:// and external URLs for many of the transactions).

[cs224]

Just a first quick reply about Accessed Nextcloud directly on the AIO Apache port via SSH I wanted to post the following screenshot of the DevTools network logs:

It shows (in my opinion) that this SSH tunneling works also for the background requests. At the bottom you can also see an empty JavaScript console. There are some errors at the beginning after page load, but once the page is loaded everything looks like on a non SSH tunneled version through the Traefik proxy. This is why I currently believe that the issue is not related to Traefik, as I believe that I bypass it with this test.

I did not tell before, but I am usually on Brave browser and the problem appears on a relatively long notes document. I’ve just started two tests, one with Brave on a small document and one with Firefox on a small document, to see if the problem still reappears.

I’ll reply in more detail once those tests have finished.

[cs224]

I have an update. I tried the “Always keep these sites active” under the “Settings → System” section that says: “Sites you add will always stay active and memory won’t be freed up from them”. This did not help.

Then I started the brave-browser with the following additional flags:
–disable-background-timer-throttling : Disable task throttling of timer tasks from background pages.
–disable-backgrounding-occluded-windows : Disable backgrounding renders for occluded windows; mainly for tests to avoid nondeterministic behavior.
–disable-renderer-backgrounding : Prevent renderer process backgrounding / priority lowering for invisible pages.

And with all of these three flags set the problem disappears in the set-up with and without Traefik. I will continue to try if fewer of those options work aswell, I consider this a first success.

Perhaps the root cause of the issue had nothing to do with me installing mailu on the home server behind Traefik. Perhaps this was a coincidence and some browser update brought in a change in behaviour.

[cs224]

As far as I can tell right now it seems that “–disable-background-timer-throttling” is enough to make the problem disappear.