The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution. It aims to be a light solution, easy to use, easy to install, easy to configure.
If well-known URLs are not configured (well-known section in configuration file), you can try
Contact group method: groups are separate VCards (or the method used by your other clients)
If you're proxying Radicale with a base path, e.g.
/radicale/ instead of just
/, make sure that
base_prefix is set correctly in your server configuration!
You might also have to set up well-known URLs on your forwarding proxy.