How to properly capture web app errors in Global.asax

In the Application_Error event, I get the last error via:

Exception lastError = Context.Server.GetLastError();

which always yields the same error: Exception of type 'System.Web.HttpUnhandle开发者_StackOverflowdException' was thrown.

How do I get to the actual error that occurred?

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Exception objErr = Server.GetLastError().GetBaseException();

Also read this complete refernece: How to create custom error reporting pages in ASP.NET by using Visual C# .NET