@nelsonnc Sounds a bit like STP issue to me as well. The quickest way to check is to connect a dumb mini switch between that client and your building switch. See if that makes a difference.
How do you know the client can reach the FOG server? When it’s booted to it’s OS from disk, can you open that exact URL in the browser on that client? http://dlk.fog.local/fog//index.php (double slash is not an issue)