After domain mapping: browser request returns default apache page

The Problem

I'm running a site locally: apache on my local dev host.

I've set up multisite and installed the Domain Mapping plugin.
My site is called 'multisite'. I have an entry in my hosts file for 'multisite2'.

I've created a network site called 'multisite2'.

However, when I attempt to navigate to it in my browser, I get the default apache page.

My installation process

This is the first time I've set up multisite, so I'm probably doing something wrong.
I've closely followed the instructions in the codex for setting up a multisite installation for wordpress, including editing my wp-config.php.

What could I be doing wrong?