Open System Settings → Privacy & Security and there, next to AlternativeVPN, click Open Anyway. Alternatively, right-click the app → Open.
For AlternativeVPN to establish an encrypted connection, macOS needs your one-time permission to add a VPN configuration.
Quit AlternativeVPN and drag the app from the Applications folder to the Trash.
Questions about the installation? Write to us anytime at support@alternativevpn.com.