Spurious access denied errors

Dear list,

I've installed and configured mediawiki as follows (on top of default
Ubuntu 16.04 Apache/2.4.18 installation):

*Everything works*, i.e. client successfully receive all pages with
appropriate HTTP statuses in both client and Apache access log. However,
for each request like /wiki/test I see the following extra message in

If I remove <Directory /var/www> clause, these messages disappear. They
trigger fail2ban and are generally confusing. What may be causing them
and how to make them stop?