Validation Server logs show error "Access Denied Provider [VSRadiusClient] failed to invoke authentication request [-3] with error", "StatusMessage: Internal error." Thread-7356 VSAuthOTPStandardControllerImpl.cpp
VIP Enterprise Gateway
VIP Healthcheck Service monitors connectivity to the VIP Cloud and will signal the validation server(s) to enter or exit Automatic Business Connectivity(ABC) mode and send notification emails. Network flapping can cause rapid connects\disconnects to the VIP Cloud, resulting in 'rapid fire' on and off signals from the Health Check service to the Validation Server. This could cause the Validation Server to be in an ABC state while awaiting an exit signal.
Set Health Check settings to compensate for network flapping by setting timeout values to 30 seconds (or more, if network issues persist).