Most of the times disabling/enabling the client is enough to restore the regular (authenticated) connection. There is no difference doing it in the system icon or the main window.
enable/disable client (either from the system icon or the main
window)
-this is usually enough to restore the regular network connection.
-if fails, repeat enable/disable client.
-if fails again, stop/start the service in Administrative Tools \
Services.
--- In some rare situations even after this the client fails to connect.
The only solution left is a reboot...