On a fresh Windows Server 2008 R2 when you try to run the updates for the fist time you get an error saying:

Windows could not search for new updates

An error occurred while checking for new updates for your computer.

Error(s) found:

Code 8024402f

Windows Update encountered an unknown error.

Error Code 8024402F

Windows Update Error

Possible reason:

You add the server to a domain and/or promote it to a domain controller before running Windows Update for the fist time.

Resolution:

Download Windows6.1-KB947821-v22-x64 KB and run it manually.

It will install the KB and after that you can check and install updates from your regular screen.