SSH to Ubuntu host from Ubuntu VirtualBox guest?

I want to SSH into my host (Kubuntu 12.04 64bit) from a VirtualBox guest running 32bit Ubuntu 12.04. The host has the latest VirtualBox from the Ubuntu repositories (4.1.12). The guest is a preconfigured VM that I downloaded from VirtualBoxImages.com .

The problem is that my sshd_config doesn't allow PubkeyAuthentication to log in, and I need to be able to use PasswordAuthentication from this VirtualBox guest (for reasons that may not be within the scope of this question).

My /etc/ssh/sshd_config file probably needs to look like this:

PasswordAuthentication no

Match Address 192.168.56.0/24
    PasswordAuthentication yes

When I add the match block to sshd_config, ssh terminates with the following message: init: ssh master process (7352) terminated with status 255

Why? What am I doing wrong? I'm using almost the same match block as in the past, so I'm confused.

This question is related but didn't help me: How to allow SSH password authentication only from certain IP addresses?

I'm guessing my problem might be related to the VirtualBox network interface...

In VirtualBox, I use "Host Only" for adapter 1 (default vboxnet0). This way the host has interface vboxnet0 with IP address 192.168.56.1. That's why my above match block IP address.

(I also set adapter 2 to "NAT" so my guests can access the external internet). For testing, I set promiscuous mode to "Allow All". I can ping both ways. And I can SSH from the host to the guest (the reverse way I want to connect).

The host runs denyhosts, but I stopped the service while testing.