FOG needs to be able to resolve the name you defined as a host name in fog to the target system using DNS. So if you can open a command prompt and ping Win10_AT and it works then you have everything setup and fog should resolve and show these systems as up. The only other thing is FOG doesn’t use the icmp ping command to check status but FOG tries to connect to udp port 445 on the target computer. So you need to make sure that udp port 445 is enabled in the target computer’s firewall.
So to restate this in list form:
The hosts to be able to be resolved by name by DNS The host have udp port 445 open in the windows firewall.This is only informational (green or red mark in the host list) and does not impact the function of fog if you choose to ignore it.