Apache: couldn't perform authentication. authtype not set

I had this error in my /var/log/apache2/error.log file:

configuration error:  couldn't perform authentication. AuthType not set!: /~baldho/owncloud

Since the problematic path is a user directory, I added a Satisfy Any option to my Directory directive in my /etc/apache2/mods-enabled/userdir.conf file, like so:

<Directory /home/*/public_html>
    [...]
    Satisfy Any
    [...]
</Directory>

And the problem went away.