How can I use the IIS substatus codes (sc-substatus) found in the logs to diagnose a 500 error?

IIS substatus codes provide more specific information about the type of 500 error. For example, a 500.19 often indicates a configuration issue, while a 500.100 signals an ASP error. Microsoft provides documentation listing the common IIS substatus codes and their meanings. Searching online for "IIS substatus codes" will provide links to the official documentation.