Wake-on-LAN stops working after a few hours

I have set up Wake-on-LAN on my desktop computer. I test the feature and it works fine.  I have even let the computer time-out into sleep mode and the feature still works. But then when I leave for a while (a few hours) and try it then, nothing happens.  I have followed all the settings in the guide, but am having trouble with this one. It seems that the computer is going into a certain power-state that is incompatible with Wake-on-LAN and I want to figure out how to re-configure the computer so that doesn't happen.  Windows 10 Pro.