On the bottom right-hand side of the TotalAV VPN screen, you will see a toggle called Killswitch.
The Killswitch will block all traffic to the internet and protect your IP address from being exposed in case your VPN connection is interrupted.
If you have Killswitch enabled and you are disconnected from VPN, you will not be able to access the internet until either you reconnect to VPN or turn the kill switch back on.