This is the exact message:
Secure VPN Connection terminated by Peer
Reason 427: Unknown Error Occurred at Peer
I checked the log and it appears that it fails authentication. The vpn concentrator can not seem to find the RADIUS server. Or its request to the RADIUS appears server to timeout. It then logs a message that the authentication server is not available. But when checking the log of the RADIUS server I find that it was available at that time. Any ideas?