Both remote hubs (Main/Backup) are running in a multi NIC environment.
192.168.0.3 - UIM Hub IP.
10.0.0.3 - IP for robot communication.
192.168.0.4 - UIM Hub IP.
10.0.0.4 - IP for robot communication.
If you use "Specified Hub (IP/name)," the robot attempts to resolve the hub name using UIM Hub IP. In this example below it does not work because the robot is not able to communicate to the UIM Hub IP.
Please use "Specified Hub (domain name)" set "robot communicatable IP Address" or "robot resolvable hostname" so that the robot attempts to resolve the hub using the local network.
In this example, you can assign "10.0.0.4" or "robot resolvable hostname" for "Specified Hub (domain name)."
If the controller probe finds the "Specified Hub (domain name)" setting, it will override "Specified Hub (IP/Name)".
The configuration key in the robot.cfg is "secondary_hub_dns_name"