Лучше сразу задать вопрос
Unable to connect to libvirt qemu:///system.
authentication unavailable: no polkit agent available to authenticate action 'org.libvirt.unix.manage'
Libvirt URI is: qemu:///system
Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/connection.py", line 956, in _do_open
self._backend.open(connectauth.creds_dialog, self)
File "/usr/share/virt-manager/virtinst/connection.py", line 172, in open
conn = libvirt.openAuth(self._open_uri,
File "/usr/lib64/python3.8/site-packages/libvirt.py", line 104, in openAuth
if ret is None:raise libvirtError('virConnectOpenAuth() failed')
libvirt.libvirtError: authentication unavailable: no polkit agent available to authenticate action 'org.libvirt.unix.manage'