Do you have a special vhost for nextcloud?
If nextcloud is served through /etc/apache/sites-enabled/default-ssl.conf it should pick up those values I guess. See /etc/univention/templates/files/etc/apache2/sites-available/ssl.d/10hsts
I see on a system - where I didn’t configure a subdomain - that for the well-known part I have created a file: /etc/univention/templates/files/etc/apache2/sites-available/ssl.d/50nextcloud-wellknown
With:
### https://docs.nextcloud.com/server/15/admin_manual/issues/general_troubleshooting.html#service-discovery
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteRule ^/\.well-known/host-meta /nextcloud/public.php?service=host-meta [QSA,L]
RewriteRule ^/\.well-known/host-meta\.json /nextcloud/public.php?service=host-meta-json [QSA,L]
RewriteRule ^/\.well-known/webfinger /nextcloud/public.php?service=webfinger [QSA,L]
RewriteRule ^/\.well-known/carddav /nextcloud/remote.php/dav/ [R=301,L]
RewriteRule ^/\.well-known/caldav /nextcloud/remote.php/dav/ [R=301,L]
</IfModule>
In it and passed it to default-ssl.conf
Best, Bernd