VPN connections between your Terminal (BATM) and the host (CAS) are absolutely critical.
This error indicates that you’ve instructed the Terminal to force VPN connections, and the connection failed in some way.
SOLUTIONS:
Check that you have a usable Internet connection.
A VPN connection will always fail if there’s no Internet available for connecting to CAS.
Have you created a Terminal certificate?
Is the firewall port open to the VPN?