OK, I have read, and searched, and searched the other WSUS sites, and cannot get this fixed. Here's the lowdown.... I installed WSUS on one server for testing, added the GPO, and everything looked like it was working..... PC's showing up, downloads downloading, etc. Well, I decided that server wasn't appropiate for this so just decided to do a full install on a new server.
So, I got the new server up and running and now, about 2/3 of my PC's are getting this crappy 0x8024401B Error, which I have found means "Proxy Authentication Required". The thing is, there is no difference between some of these computers and the ones that are communicating just fine with WSUS. And yes, we have an ISA 2000 server as our proxy server, but the WSUS is local. I have added the WSUS server as an exception in IE with manual proxy settings in there, I have turned off IE settings all together to where I couldn't browse anything but local servers, and I have used Automatic Detect IE settings to read from our DHCP 252 WPAD push, and I cannot figure out WHY these other computers keep wanting to go out through the proxy server. This is a local WSUS server!!!
And, why did it work at one point on the old server (which happened to be the ISA Server itself), and then I totally reinstall the WSUS server elsewhere and only 1/3 of them still work. I have even checked my AU settings in the registry and they are correctly pointing to the WSUS server. I have run the client testing tool and it all passes, and still, I cannot get passed this 0x8024401B Error "Proxy Authentication Required". IT DOESN'T NEED TO GO THROUGH THE PROXY! The WSUS server is on the same subnet, and is even in the LAT on the ISA Server just in case. Any ideas PLEASE???