Hi @Jeremy_Vies,
Before diving into the technical details, one thing worth clarifying: the image you’re using is not the official Nextcloud Docker image. The repository at GitHub - nextcloud/docker: A community maintained docker micro-image for deploying Nextcloud on container platforms · GitHub carries this warning right at the top of its README:
This image is maintained by community volunteers and designed for expert use. For quick and easy deployment that supports the full set of Nextcloud Hub features, use the Nextcloud All-in-One docker container maintained by Nextcloud GmbH.
The officially supported Docker deployment is Nextcloud AIO (All-in-One), maintained by Nextcloud GmbH. With AIO, Nextcloud Office works out of the box — the Collabora integration, WOPI configuration, and internal networking are all handled automatically.
What’s actually failing in your setup:
Looking at your logs, the root cause is these two lines:
192.168.81.254 - "GET /index.php/apps/richdocuments/wopi/files/... HTTP/1.1" 500
192.168.81.254 is your CODE server (COOLWSD) trying to fetch the document from Nextcloud via the WOPI protocol — and getting HTTP 500 back. Everything else follows from that:
- The
400onproxy.php(WebSocket) is a consequence — Collabora can’t open a document it was never able to load - The
404s for SVG files are cosmetic and irrelevant
The most likely cause in a community Docker setup is that wopi_allowlist in config.php does not include the IP range of your CODE container (192.168.81.x). Since Nextcloud 22, WOPI requests from IPs not in the allowlist are rejected. Getting this right in a custom Docker + Traefik setup requires manual network configuration that AIO handles automatically.
To confirm the exact error you would need the nextcloud.log entries at the same timestamp — but honestly, if you’re not already deeply familiar with Nextcloud’s Docker networking requirements, switching to AIO will save you a lot of this kind of troubleshooting.
If you want to stay with the community image, the proper approach is to run Collabora CODE as a separate container with a correct reverse proxy configuration — not as the integrated richdocumentscode app. This HowTo covers exactly that setup, including network configuration and the domain-based allowlist approach: Collabora CODE for Nextcloud with Docker
h.t.h.
ernolf