PRB: "Unable to start debugging on the Web server" error message when you debug ASP.NET applications


Symptoms


When you debug an ASP.NET application in Visual Studio .NET, you may receive the following error message:
Error while trying to run project : Unable to start debugging on the web server. Would you like to disable future attempts to debug ASP.NET pages for this project?
In Visual Studio 2005 .NET, you receive the following error message:
Unable to start debugging on the web server. An authentication error occurred while communicating with the web server. Please see Help for assistance.

Cause


This error occurs because Microsoft Internet Information Server (IIS) is not running or is not functioning properly.

Resolution


To resolve this problem, you must restart IIS. To do this, type iisreset at a command prompt.

Make sure that the IIS application is configured to use Integrated authentication so it will pass your credentials that are needed to launch the debugger. The anonymous account does not have sufficient permissions to perform debugging.

References


For more general information about ASP.NET, refer to the following MSDN newsgroup: