Spice vm connection?

Hi, is anyone able to help me with the correct URI to use to connect Boxes to my new VM (win 7) on another machine - I feel this must be obvious but I’m getting nowhere. I have qemu+ssh://root@frontserver.lan/system working fine - but, anything I try with ‘spice:’ fails

This is the xml for ‘Display Spice’ in virt-manager:

<graphics type="spice" port="5900" autoport="yes" listen="">
  <listen type="address" address=""/>

$ virt-viewer --connect qemu+ssh://root@frontserver.lan/system


$ virt-viewer --connect spice://root@frontserver.lan/system

Fails with a graphic box:

Unable to connect to libvirt with URI:spice://root@frontserver.lan/system

Installed on the Win7 VM are ‘QEMU guest agent’ and ‘Spice Agent’ and all drivers updated from latest /usr/share/virtio-win/virtio-win.iso