If you administer WSUS you probably had this 0x8024402cerror in WindowsUpdate.log already, right?
So, let's check together:
- no WinHTTP proxy (here)? Check!
- IIS is working fine on WSUS server? Check!
- DNS resolves servername? Check!
- GPO's are flowing nicely and you have your WSUS server defined under WUserver and WUStatusServer in HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate? Check!
Still having this error? Go to:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU and check if you have UseWUServer=1 DWORD entry. I didn't have it and it was the reason of problems, despite that GPO's were ok.
For reference I suggest this technet article.
