What role do 'Default Documents' play in troubleshooting a 403.14 error for an MVC site on IIS?

While ASP.NET MVC applications primarily rely on their routing engine to serve content, 'Default Documents' in IIS can still play a role in troubleshooting a 403.14 error, especially if the MVC application fails to initialize or route requests properly. If the MVC routing mechanism isn't correctly engaged (e.g., due to handler mapping issues, app pool problems), IIS might fall back to looking for a default document (like `index.html`, `default.aspx`). If no such document exists in the requested directory and directory browsing is disabled, you'll get the 403.14 error. Therefore, ensuring your IIS application has configured default documents (even if MVC usually overrides this behavior for its routed paths) can sometimes provide a fallback or help diagnose if the issue is *before* MVC routing takes over.