Download page Deploying a Wake on LAN Proxy for Distributed Environments.
Deploying a Wake on LAN Proxy for Distributed Environments
The UMS is residing outside the network which contains your devices, so it cannot wake up your devices by Wake on LAN.
You want the UMS to wake up your devices from outside their network.
If you are using UMS version 5.02.100 or higher and devices running Linux version 5.09.100 or higher, you can make a device act as a proxy which sends the Wake on LAN packets on behalf of the UMS.