[ovirt-users] Unable to start nor to migrate vm

Hi, I'm having trouble with our ovirt environment, i'm not able to start VMs nor to migrate running ones, i'm getting the following error: libvirtError: error from service: ListActivatableNames: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken. Any idea what causes this error? oVirt (oVirt Engine Version: 3.5.6.2-1.el7.centos) running on: CentOS Linux release 7.2.1511 kernel : 3.10.0-327.4.4.el7.x86_64 Nodes: Red Hat Enterprise Linux Server release 7.2 (Maipo) vdsm-python-4.16.30-0.el7.centos.noarch vdsm-cli-4.16.30-0.el7.centos.noarch vdsm-yajsonrpc-4.16.30-0.el7.centos.noarch vdsm-xmlrpc-4.16.30-0.el7.centos.noarch vdsm-hook-vmdisk-4.16.30-0.el7.centos.noarch vdsm-jsonrpc-4.16.30-0.el7.centos.noarch vdsm-hook-floppy-4.16.30-0.el7.centos.noarch vdsm-python-zombiereaper-4.16.30-0.el7.centos.noarch vdsm-4.16.30-0.el7.centos.x86_64 vdsm-hook-vhostmd-4.16.30-0.el7.centos.noarch Thanks for any hint/help. rgds, Arsène