I can’t ping my freshly loaded OSMC on a pi3 from 2 different windows 10 boxes and also a linux machine. They all report Destination host unreachable.
What does the machine responsible for DHCP say in its logs? Is there a lease given, discover, offer, request, anything?
You might try pinging the Pi with its MAC, though. Use
arping on the Linux machine for this.
What does it show in the network section of My OSMC?
Ironically, a simple reboot of my router fixed it. Whereas all other functionality was fine with the router.