In the servers section, select the server in which country you prepare. The first server indicates the date when the subscription ends, it DOES not work.
If there are no servers or they are not working, click "update all".
After that, go back to the screen as in the screenshot and click "Load core" to start the VPN.
To update: Servers > at the bottom "update All»
Make sure you have the correct local time on your device!