Access to the collabora server via VPN

I use Tailscale’s network to access my Nextcloud instance away from home.
I also use the Nextcloud Office suite to be able to edit my documents on the cloud, but I can’t do it remotely because the Collabora server hosted on nextcloud doesn’t seem to be reachable.
How can I change the collabora settings to be able to access the server via vpn?

Thanks a lot

Nextcloud Collabora integration

read, understand the requirements and add this to your VPN