Nextcloud: Your web server is not properly set up to resolve "/.well-known/caldav"

What the message looks like

Your web server is not properly set up to resolve "/.well-known/caldav". Further information can be found in the documentation.
Your web server is not properly set up to resolve "/.well-known/carddav".

Common causes

• The nginx server block has no redirect for the two .well-known paths.
• A reverse proxy in front of Nextcloud answers /.well-known/ itself or does not pass it on.
• On Apache, .htaccess is ignored because AllowOverride is not All or mod_rewrite is off, or the file is outdated.
• Nextcloud is installed in a subfolder, so the well-known path must sit on the domain root.

Check

1. What does caldav answer?
   curl -sI https://cloud.example.com/.well-known/caldavCopy
2. What does carddav answer?
   curl -sI https://cloud.example.com/.well-known/carddavCopy
3. Is there a rule in the nginx config?
   nginx -T 2>/dev/null | grep -n well-knownCopy
4. Which URL does Nextcloud assume?
   sudo -u www-data php occ config:system:get overwrite.cli.urlCopy

Fix

• In nginx, add to the server block: location = /.well-known/carddav { return 301 /remote.php/dav/; } and the same for caldav. Then nginx -t and systemctl reload nginx.
• With a reverse proxy, put the two redirects on the proxy, or pass /.well-known/ through to Nextcloud.
• On Apache, enable mod_rewrite (a2enmod rewrite), set AllowOverride All for the Nextcloud folder, then run sudo -u www-data php occ maintenance:update:htaccess.
• Check again with curl -sI: you want 301 and a Location ending in /remote.php/dav. Then reload the overview page.

FAQ

Does this block calendar and contact sync?

Not if you enter the full address https://cloud.example.com/remote.php/dav in the client. Without the redirect, automatic discovery by just the domain name fails.

Is a 302 or a 200 also fine?

The check expects a redirect to /remote.php/dav. A 200 with a page body or a 404 means the path is not handled, so the warning stays.