Unable to start debugging on the web server. Unable to connect to the webserver

Question

I am running Visual Studio 2008, IIS 7.5 on Windows 7 x32. I am able to run the ASP.NET web site in IIS 7.5 without debugging just fine, but when I press F5 to debug it, I get:

Unable to start debugging on the web server. Unable to connect to the webserver. Verify that the web server is running and that incoming http requests are not blocked by a firewall..

Answer 1

In VS, right click on your web project --> Properties Go to the Web tab.

Make sure the appropriate radio button is selected (Use VS Dev Server, Use Local IIS Web Server, etc)

After a computer freeze I've had that value change on me.

Another thing to try:

run "iisreset" from an administrative command prompt (basically just restarts the IIS service)

Answer 2

Check if your IIS is running, if isn't try to initialize him and run again on VS.

Answer 3

Try the following:

1. Open IIS > Add a new Application (not a virtual folder) to the Default Website.
2. Make sure the application runs under the right .net framework version (i.e. DefaultAppPool ussually runs under .Net 4.0)
3. Map the application in IIS to the right project folder (where your bin and obj folder appear after a build)
4. In IIS, right-click the application, and click 'Manage application' > 'Browse'. This will launch an internet exploreren to the right path. This could be localhost:80/Shop instead of the expected localhost/Shop (caused by for example a reservation for other applications of the direct localhost/ location)
5. In Visual Studio > go to the application properties > Web > check Use local IIS > and set the correct location of your application in IIS (you should know this from step 4)

Answer 4

Verify that your web.config has the following entry:

<compilation debug="true" targetFramework="2.0" />

Note: If you are targeting framework 1.1, then obviously change the 2.0 to 1.1.

UPDATE:

The `targetFramework` attribute is new in .NET 4.0 and later, so to enable debugging on .NET 2.0 and earlier, then you cannot use the `targetFramework` attribute, like this:

<compilation debug="true" />

Answer 5

Just to check: See if Windows Authentication is enabled or not? It should be enabled. Internet Information Services (IIS) Manager > Expand PC/Server Name > Expand Sites > Select Default Web Site > Select Authentication. It should be enabled.

Answer 6

Make sure that the port defined in the Project Url under the Web tab of the properties of the web project is the same one as defined in the IIS Manager.

I had this issue and fixing the port solved the problem for me.

Answer 7

I had a case, where I could load the site in chrome, but deugger could contact the server. Turns out Chrome auto-maps .localhost addresses, but VS does not.

Adding the localhost address to my hosts file solved the issue.