You need a LAN network component if there isn't an internet connection (offline).
As a network component are suitably a local network, hub, switch, router, DSL modem, cable modem, AirPort (WLAN). If such a network component isn't available, please use another browser e.g. Firefox.

• 1 At Show select Network Port Configurations.
• 2 If deactivated LAN network components are still available, you activate these.
• Otherwise you click on New ... and select a suitable configuration.
• 3 Click on: Apply Now

At first if the lock symbol is closed, you must open the lock. You need administrator rights for the configuration.