I Personally use NGINX Proxy Manager,
If you look at Issue#70 on GithubFor NGINXReverseProxyManager , it has all the information you need to set up Collabora on a Reverse proxy with NginxProxyManager
github.com/jc21/nginx-proxy-manager/issues/70
Fixed all of my issues.
Was able to eventually connect to Toronto using Next gen and :test Build, Would not download though, Disabled strict Port Forwarding, and is downloading now!