Nextcloud Nginx CalDav CardDav Docker

Just installed nextcloud on my NAS via Container. Everything is working fine if I connect over the browser.

If I go to overview it tels me that the webserver is not setup correctly.

On my Synology NAS I already use a Calender with CalDav and this works perfectly.

Is there a way to connect both Calender, the nextcloud Calender and the “old” Synology Calender together? Or maybe connecting is not ther right word. Maybe it is possible, that NextCloud write directly into the Synology Calendar?

I use Nginx, wich is not runing in Docker.

My goal is, to be able to connect my new Fairphone with /e/ OS to my selfhosted nextcloud and use CalDav and CardDav. If I log in with my phone I get an error because my carddav and caldav are not setup correctly.

Thanks for the help