I started applying updates to our from our WSUS server, which is running off of a Windows 2012 R2 server.
After applying updates to a group of servers, including the WSUS server, after the reboot from applying updates overnight, all the Windows 2008 R2 servers we have checking into it, decided to stop checking in with the WSUS server, with an error code of 80072EFE. However, they are on the same LAN, can ping the WSUS server, can access it on ports 8530 and 8531.
This is happening with Win2008 R2 servers that weren't updated, either. So, my guess is something changed on the WSUS server.
The crazy part is, I brought up an unpatched new WSUS server to test, and I can't get the Win2008 R2 servers to check into it. I can get ALL other versions to check into both WSUS servers. (Including Win2003, Win2008, Win2012, Win2012 R2).
I have tried multiple suggestions on troubleshooting, including info found here: http://social.technet.microsoft.com/Forums/windowsserver/en-US/170831ee-cf90-44b5-b7c7-16817a9483db/2008-server-r2-clients-will-not-check-into-wsus-30-sp2?forum=winserverwsus
I have gone through a complete reset of Windows Update on one of the Win2008 R2 servers, with no results. That includes stopping the bits and wuauserv services, deleting the SoftwareDistrubution folder, restarting the services. Re-registering all the dll's listed on Microsoft's site. Nothing is helping. :(