Authentication error when launching virtual manager

Launching virtual manager as non root users gives authentication error. 

   

 check user if part of libvirt group if not add user to group 

 csr@MainPC:/etc/modprobe.d$ groups csr

csr : csr cdrom floppy sudo audio dip video plugdev users netdev bluetooth lpadmin scanner

csr@MainPC:/etc/modprobe.d$ sudo usermod -a -G libvirt csr

csr@MainPC:/etc/modprobe.d$ groups csr

csr : csr cdrom floppy sudo audio dip video plugdev users netdev bluetooth lpadmin scanner libvirt

csr@MainPC:/etc/modprobe.d$ cd

csr@MainPC:~$ 

 

 launch virtual manager