root@ariel-pc:/home/ariel# software-center
/usr/bin/software-center:25: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk, GObject
/usr/share/software-center/softwarecenter/ui/gtk3/views/purchaseview.py:29: PyGIWarning: WebKit2 was imported without specifying a version first. Use gi.require_version('WebKit2', '4.0') before import to ensure that the right version gets loaded.
  from gi.repository import WebKit2 as webkit
/usr/share/software-center/softwarecenter/ui/gtk3/widgets/symbolic_icons.py:23: PyGIWarning: PangoCairo was imported without specifying a version first. Use gi.require_version('PangoCairo', '1.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk, Gdk, GLib, PangoCairo
2017-04-04 05:00:43,872 - softwarecenter.ui.gtk3.app - INFO - setting up proxy 'None'
Traceback (most recent call last):
  File "/usr/bin/software-center", line 130, in <module>
    app = SoftwareCenterAppGtk3(options, args)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 338, in __init__
    self.icons)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/session/appmanager.py", line 66, in __init__
    self.oauth_token = helper.find_oauth_token_sync()
  File "/usr/share/software-center/softwarecenter/backend/ubuntusso.py", line 143, in find_oauth_token_sync
    sso.find_credentials()
  File "/usr/share/software-center/softwarecenter/backend/login_impl/login_sso.py", line 74, in find_credentials
    self.proxy.find_credentials(self.appname, self._get_params())
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 70, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 145, in __call__
    **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 651, in call_blocking
    message, timeout)
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: 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.