[libvirt-users] Cannot get interface MTU - qemu quest fails to start off OpenVswitch

hi guys I have a qemu guest and openvswitch bridge and the guest fails to start: $ virsh start work8 error: Failed to start domain work8-vm-win2016 error: Cannot get interface MTU on 'ovsbr0': No such device LXC guest which uses the same source network starts just fine. I'm on Centos 7 with openvswitch-2.9.0-3.el7.x86_64 from centos-openstack-pike repo and libvirt-4.5.0-10.el7_6.7.x86_64. Would anybody care to suggest a possible reson(s) causing the failure? many thanks, L.