Post-Install WSUS Configuration Fails With Error “HTTP status 503: Service Unavailable.”
I encountered this issue in my lab, when trying to setup WSUS for my SCCM server (to use as a Software Update Point). So after installing the WSUS role (using a SQL database, and not the WID option), you will notice that there are some post-install configuration required. When you click on the ‘Launch Post-Installation…