Because there is no example i wil share my working configuration for the well-known carddav/caldav with the pound reverse proxy. Nextcloud is running on domain.de/cloud
# Service Discovery Calendar/Contacts for Nextcloud
Service
URL "/.well-known/caldav"
HeadRequire "Host:? (domain.de).*"
Redirect 301 "https://domain.de/cloud/remote.php/dav/"
End
Service
URL "/.well-known/carddav"
HeadRequire "Host:? (domain.de).*"
Redirect 301 "https://domain.de/cloud/remote.php/dav/"
End