Wake on LAN uses IP broadcasts to send messages, by default these packets will not leave the subnet. To send the wake on LAN action to a different subnet you have 3 options:
- Configure your routers to allow directed broadcasts
- Install a separate scanning server on each subnet. (This requires a license that allows more than 1 scanning server)
- Use VLANs to connect your scanning server part directly to each subnet.
The following links could also assist in configuring WOL further:
https://www.howtogeek.com/70374/how-to-geek-explains-what-is-wake-on-lan-and-how-do-i-enable-it/
https://www.unifiedremote.com/tutorials/how-to-configure-wake-on-lan-on-windows
http://windows7-issues.blogspot.be/2011/03/wake-on-lan-wol-for-windows-7-made-easy.html
https://www.groovypost.com/howto/enable-wake-on-lan-windows-10/