[libvirt] Virtual machine

My Ubuntu16.04.5 server is installed qemo-kvm and libvirt-manager but virt-manager is not starting. consequently when I install vncserver the keyboard does not work on the virtual machine. But in ubuntu 14.04 it works perfectly. can my help ?? ERRO when try run : virt-manager Could not connect: Connection refused Failed to connect to Mir: Failed to connect to server socket: No such file or directory Unable to init server: Could not connect: Connection refused (virt-manager:7676): Gtk-CRITICAL **: gtk_settings_get_for_screen: assertion 'GDK_IS_SCREEN (screen)' failed