Apache: (403 Forbidden) in response to PROPFIND request

This error would be found in /var/log/apache2/error.log

If that happens in a user public_html, open the file /etc/apache2/mods-enabled/userdir.conf and make sure PROPFIND is included in the permissions:

<Limit GET POST OPTIONS PROPFIND MKCOL PUT>
    Order allow,deny
    Allow from all
</Limit>
<LimitExcept GET POST OPTIONS PROPFIND MKCOL PUT>
    Order deny,allow
    Deny from all
</LimitExcept>

The same Limit tag could be found or added in your /etc/apache2/sites-enabled/default file for a general effect.

This did the trick for me on my Debian system.