If your device is powered on but show up as Offline under Menu -> Devices your device probably blocks ping attempts.
On Windows, follow these steps to remedy the issue:
Change from Public to Private network
- Go to Settings -> Network and Internet -> Change connection properties
- Change Network profile from Public to Private
- Open Search bar on Windows (Windows-key)
- Search for HomeGroup
- Press Change advanced sharing settings...
- Under File and printer sharing, check the option Turn on file and printer sharing
- Press Save changes
You should now be able to see your device as Online.