For Wake on LAN (WOL) purposes a Scalability Server by default only knows about it's own subnet and can only wake up targets from that subnet.
How can you use Wake on LAN on a remote subnet ?
CA Client Automation - All Versions
Once an agent from a remote subnet registers to the Scalability server the network details of this PC are reported to the Common Service on the Scalability Server and it can then wake up any target PC on that same subnet.
Ensure at least one agent from each remote subnet has successfully registered to the Scalability Server being used as the Boot Server