[Fixed] Collabora Docker and Nextcloud 21 - "Failed to read document from storage"

Hi there,
I have the following issue:
I set up the collabora docker container, and ran it with the following command:

sudo docker run -t -d -p -e 'domain=server\\.drink23\\.de' --restart always --cap-add MKNOD collabora/code

whereas server.drink23.de is my nextcloud address.
In the Nextcloud “Collabora Online” settings, when entering my url https://collabora.drink23.de, it tells me “Server is reachable.”
If I want to open a document however, I get the following error: “Failed to read document from storage. Please contact your storage server administrator”.

I already tried suggestions from the previous topics, but none of them have worked so far.

I am new to this forum, so please correct me, if something is wrong.
Also, if you need any type of config or log file, just let me know.

Short summary of my setup:

  • Nginx as Webserver for Nextcloud
  • Caddy v2 as reverse proxy for Nextcloud and Collabora
  • Fedora 34

Fixed the issue by completely removing the container and pulling the newest version and running that.