Vercara UltraDNS traffic management capabilities utilize UltraDNS probes located around the world to determine the accessibility of your defined DNS records (hosts and applications). When your host is unreachable, your query responses will be modified based upon the actions you have configured in UltraDNS. Actions may include notifications and taking resources out of service.
A firewall, or similar devices, can block the IP addresses that are associated with the UltraDNS traffic management probes and make your host appear to be unreachable (down) when in reality, your host is fully available (up) and operational.
Please make the necessary modifications to your firewall security policies to include the following IP addresses associated with UltraDNS probes used for traffic management.
All Traffic Management IP Addresses for All Probing Regions:
https://ultra-portalstatic.ultradns.com/static/console/docs/Traffic_Management_IPs_for_Probing.html