Collabora Error opening files

If you’re using the built-in CODE server (richdocumentscode), you don’t need to configure anything manually—just make sure the “Use built-in CODE server” option is enabled.

If it still doesn’t work, it’s likely because the client doesn’t trust the self-signed certificate, or it might still be trying to connect via the URL you previously used. In that case, try switching to “Use your own server” and then back to “Use built-in server”—that can sometimes reset things.

That said, this setup isn’t exactly ideal. Even though it can work in theory, to avoid issues like this, you should always access your Nextcloud via its domain name, don’t switch between using the IP address and the domain.

Check out 101: Split-Brain DNS (split-horizon) to learn how you can configure your local network to always access Nextcloud via domain name, even from within your LAN.