For some reason SCCM 2012 ( System Center Configuration Manager 2012) may report the following error:
Portal Web Site Control Manager detected PORTALWEB is not responding to HTTP requests. The http status code and text is 500, Internal Server Error.
Possible cause: Internet Information Services (IIS) isn't configured to listen on the ports over which PORTALWEB is configured to communicate.
Solution: Verify that the designated Web Site is configured to use the same ports which PORTALWEB is configured to use.
Possible cause: The designated Web Site is disabled in IIS.
Solution: Verify that the designated Web Site is enabled, and functioning properly.
For more information, refer to Microsoft Knowledge Base.