I am trying to add or remove applications from Ubuntu Software Center but ending up with the following error
Software can't be installed or removed because the authentication service is
not available.
(org.freedesktop.PolicyKit.Error.Failed: ('system-bus-name', {'name': ':1.74'}):
org.debian.apt.install-or-remove-packages
apt-get install or apt-get remove works good from command line, but doesn't in USC
Any help ???