I have a single WSUS server (Windows 2012 R2) built new in my domain. I can successfully pull (via GPO) over 1900 machines. I am sure that I'm only missing a few machines (which are 2K8 terminal servers). All other PCs and laptops and servers are successfully communicating with WSUS.
My issue is that I have roughly 10 Terminal Servers of 35 Terminal Servers (same OU, subnet and GPO) are not communicating. I have confirmed in the registry that the servers are looking at the correct location for WSUS (port 8530). I have also attempted on one of the servers /resetauthentication /detect and I still have not seen it in WSUS after 2 hours.