Setup TriliumNext server on Synology nas with Synology Reverse proxy

[matthieubruneau]

Hello,
I am currently trying to setup TriliumNext on my Synology NAS. The docker is running fine, I can access it locally without any issue.
But as soon as I want to access it using the built-in reverse proxy, I am getting these errors (especially on mermaid-graphs).

JS Error: Uncaught error: Message: Failed to fetch dynamically imported module: 
https://*********/assets/v0.98.1/src/classDiagram-KNZD7YFC.js, Line: undefined, Column: undefined, Error object: {"str":"Failed to fetch dynamically imported module: https://*********/assets/v0.98.1/src/classDiagram-KNZD7YFC.js","message":"Failed to fetch dynamically imported module: 
https://*********/assets/v0.98.1/src/classDiagram-KNZD7YFC.js","hash":"TypeError","error":{}}, Stack: undefined

�
Stack: Error

    at Object.logError$1 [as logError] (https://*********/assets/v0.98.1/src/app_context.js:11:11536)

    at https://*********/assets/v0.98.1/src/index_jquery.js:1:1502

It's happening only when I try to access it with my reverse proxy.
Here are some screenshots of my settings:

(Also, I have never used nginx or Apache outside of the built-in from Synology, so I have no idea what is happening)
Any ideas on what is happening?

[dosubot[bot]]

Hi @matthieubruneau! I'm Dosu and I’m helping the Trilium team.

This error almost always means the Synology reverse proxy isn't forwarding requests for static assets (like dynamically imported JS modules) correctly, so TriliumNext returns an HTML error page instead of the JS file the browser expects. This is a common issue with reverse proxy setups and not specific to TriliumNext itself.

Here’s what you should check and try:

1. Headers and HTTP version: Make sure your Synology reverse proxy is set to use HTTP/1.1 and forwards these headers: Upgrade, Connection, Host, X-Real-IP, X-Forwarded-For, and X-Forwarded-Proto. These are needed for proper API and WebSocket support. The official Trilium reverse proxy example shows the required settings.

2. Buffer sizes: If you see 502 errors or asset fetch failures, increase the proxy buffer sizes. In nginx, this would be:

   proxy_buffers 16 16k;
   proxy_buffer_size 32k;
   proxy_busy_buffers_size 64k;
   

   Synology’s UI may not expose these directly, but if there’s an “advanced” or “custom” section, look for buffer or header size options. This has fixed similar issues for other users (example).

3. Asset path forwarding: Make sure the reverse proxy is not rewriting or stripping parts of the URL path for /assets/ or /api/. Requests for static files like /assets/v0.98.1/src/classDiagram-*.js must reach the Trilium Docker container unchanged.

4. trustedReverseProxy setting: In your Trilium config.ini (in the data directory), add:

   [Network]
   trustedReverseProxy=true
   

   Or set the environment variable TRILIUM_NETWORK_TRUSTEDREVERSEPROXY=true in your Docker setup. This tells Trilium to trust headers from the reverse proxy and handle HTTPS/redirects correctly (docs).

5. Browser cache: After fixing the proxy, do a hard refresh (Ctrl+Shift+R) to clear any cached JS filenames, as Trilium sometimes renames these for each release (details).

6. Diagnostics: Try accessing a static asset (like the failing JS file) directly via your public URL. If you get an HTML error page, the proxy is still misconfigured. Also, check /api/setup/status—it should return JSON, not HTML.

If you can’t find buffer settings in Synology’s UI, you may be limited by its built-in reverse proxy. In that case, consider using a custom nginx container or Nginx Proxy Manager for more control.

Let me know if you need help with any of these steps or want to share your config for review!

To reply, just mention @dosu.

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[rom1dep]

@matthieubruneau : is it any better with unchecking HSTS and clearing cache? It should "just work"© with the reverse proxy settings you have

[matthieubruneau]

@rom1dep
It is working better without HSTS and clearing chrome cache after. I will mark this as solved and put your reply as answer.