VS2010 error: Unable to start debugging on the web server

Question

I get error message \"Unable to start debugging on the web server\" in Visual Studio 2010. I clicked the Help button and followed the related suggestions without success.

Answer 1

I got a new PC with Windows 7. I installed VS2010 and my development environment and hoped my F5 debug problem would be gone, but it still failed to start the debugger.

This was a good clue since it ruled out the install of software.

I finally traced it down to my HOSTS file. I had an entry for some of my local websites which I can access like "http://testsite.lcl" but the IP I had assigned was my machine's IP instead of using 127.0.0.1 so it looked like a remote server to VS2010. Changing back to 127.0.0.1 resolved the issue.

Thanks for everyone's help on this.

Answer 2

What worked for me was to go into IIS at the server level, click on ISAPI and CGI restrictions, I found that aspnet_isapi.dll for asp.net 4.0 was set to Not Allowed. I set it to allowed and debugging worked. The steps are:

1. Open IIS.
2. Click on the top level
3. Select ISAPI and CGI Restrictions under IIS in the Features view
4. Examine the Descriptions and if ASP.NET v4[current version] has the Not Allowed Restriction, click on the "Allow" link in the Actions section of the dialog.

This change should take care of the problem. Note that I came up with this solution when I tried to run the web app withoug debugging and I came up with the following error:

HTTP Error 404.2 - Not Found The page you are requesting cannot be served because of the ISAPI and CGI Restriction list settings on the Web server.

Answer 3

Disable the loopback check

(original microsoft page here)

To set the DisableLoopbackCheck registry key, follow these steps:

Click Start, click Run, type regedit, and then click OK.

In Registry Editor, locate and then click the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa

Right-click Lsa, point to New, and then click DWORD Value.

Type DisableLoopbackCheck, and then press ENTER.

Right-click DisableLoopbackCheck, and then click Modify.

In the Value data box, type 1, and then click OK.

Quit Registry Editor, and then restart your computer.

Answer 4

I had the same problem. How did I fixed it.

Go to IIS (in my case IIS 7 / Windows 7). Select your web site from the list, click on .NET Compilation in ASP.NET section. Select Open Feature. Check if your Debug is set to True. In my case it was False. Once I changed it to True - I have my debug back :)

Answer 5

I had the same issue on Win7 and VS2010 (without ReSharper) and found that Skype listened on port 80. IIS listens to port 80 by default. This can occur when you set VS to debug an existing web application running in IIS instead of the built in ASP.NET debug web server.

I solved the issue by unchecking "Use ports 80 and 443 as alternatives for incoming connections." in Skype under Tools -> Options -> Connection, followed by a restart of Skype.

Answer 6

Unload project, right click "edit abc.csproj" You will see the configuration. If your project is mapped to use IIS Web Express url.

<WebProjectProperties>
<UseIIS>True</UseIIS>
<AutoAssignPort>True</AutoAssignPort>
<DevelopmentServerPort>6270</DevelopmentServerPort>
<DevelopmentServerVPath>/</DevelopmentServerVPath>
<IISUrl>http://matrimonyfree.in/</IISUrl>
<NTLMAuthentication>False</NTLMAuthentication>
<UseCustomServer>False</UseCustomServer>
<CustomServerUrl>
</CustomServerUrl>
<SaveServerSettingsInUserFile>False</SaveServerSettingsInUserFile>
</WebProjectProperties>

verify If you have started the web site in IIS http://matrimonyfree.in in this case