Open the app and try a few things.
1. Disable SecureCore and Adblocker (Netshield). Try connecting and browsing and see if it works, if it doesn’t go back and disconnect.
2. Try to disable the kill switch. Then connect and see how it works, if you lose connection, click on the big disconnect button on the main page of the app.
3. Try to select a different server from the countries tab. Sometimes, while you are connected, the VPN will lose its connection to the server, and you’ll need to manually disconnect and reconnect for everything to work.