Ssh – Cannot connect to Openstack Instance via horizon, but SSH works

I've got an OpenStack deployment running inside a VM for testing purposes. My setup is as follows: Host Ubuntu x64 with Virtualbox -> Guest Ubuntu x64 with OpenStack -> Ubuntu X64 Server Test Instances through Openstack.

I realize it is of no practical use, but as said, it is for testing purposes only. I successfully launched an instance, binding it to 11.1.0.3 and 172.16.1.1 (host is 172.16.0.1) and I can successfully ssh into it from either the host or the guest VM with ssh -i key.pem ubuntu@11.1.0.3 (or 172.16.1.1). Unfortunately, the NoVNC via Horizon does not work (Starting VNC handshake -> Failed to connect).

The relevant lines from my nova.conf are the following:

--novnc_enabled=true
--novncproxy_base_url=http://172.16.0.1:6080/vnc_auto.html
--vncserver_proxyclient_address=172.16.0.1
--vncserver_listen=172.16.0.1

So I'm not sure what's going wrong. The keypair that matches the .pem file I ssh with is of course coupled with the instance, and the instance is Active and Running.

Any help would be greatly appreciated.

Edit: nova get-vnc-console [id] novnc correctly supplies me with a link to vnc into the vm, but it also fails to connect.

Edit 2: To clarify: I have an active, running instance that successfully launched through the OpenStack dashboard. I can ping the instance, I can ssh into it (using 'ssh -i key.pem ip), but I cannot access it through VNC (specifically novnc on the dashboard). Trying to access the VM through the URL nova supplies through get-vnc-console does not work either. What I wish to do is access this instance via VNC.