You need to have the CODE (Collabora Online Development Edition) docker container running then use the app to connect your Nextcloud instance in order to use it.
If you have configured all that, then you could have some issues with the configuration.
Hmm. Well, I got Apache running on another host with HTTPS. I pointed NextCloud/Collabora to it using HTTP, which I guess won’t work. In any case, I don’t get any response connecting to port 9980 via HTTP or HTTPS.
So, it looks like HTTPS works to the Collabora Docker instance but not HTTP. NextCloud won’t let me mix protocols and I use HTTP to NextCloud. Is there any way to use HTTP with the Collabora server?