Have you checked that the username you are connecting with are member of the correct groups on the host?
What happens if you try to access libvirt from a console on the host like::
It should list like this:
Code
username@LHJ-OMV:~$ virsh list --all
Id Name State
----------------------------------------------------
username@LHJ-OMV:~$
Also check that the libvirt deamon is running on the host:
it should display: