NC 20: web server not set up properly to support "./well-known/caldav"

Solved it ! it’s due to trailing / on proxypass. I kept having remote.phpp instead of remote.php thanks to this posts : Requested uri (/cloud/remote.phpp/dav/files/mburchard/) is out of base uri (/cloud/remote.php/dav/) · Issue #20707 · nextcloud/server · GitHub && Nextcloud behind Apache reverse proxy, remote.php becomes remote.phpp - #2 by skjaeve