[iis-7.5] HTTP Error 404.3-Not Found in IIS 7.5

I'm using IIS 7.5 on Windows Server 2008 R2 x64 Enterprise Edition. In the project we have developed with ASP.NET 4.0 we used WCF Service. But it doesn't run over domain when the software is running from local computer. Otherwise, I am getting the following error:

HTTP Error 404.3-Not Found

The page you are requesting cannot be served because of the extension configuration. If the page is script, add a handler. If the file should be downloaded, add a MIME map.

This question is related to iis-7.5 mime-types

The answer is


You should install IIS sub components from

Control Panel -> Programs and Features -> Turn Windows features on or off

Internet Information Services has subsection World Wide Web Services / Application Development Features

There you must check ASP.NET (.NET Extensibility, ISAPI Extensions, ISAPI Filters will be selected automatically). Double check that specific versions are checked. Under Windows Server 2012 R2, these options are split into 4 & 4.5.

Run from cmd:

%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -ir

Finally check in IIS manager, that your application uses application pool with .NET framework version v4.0.

Also, look at this answer.


I was having trouble accessing wcf service hosted locally in IIS. Running aspnet_regiis.exe -i wasn't working.

However, I fortunately came across the following:

Rahul's blog

which informs that servicemodelreg also needs to be run:

Run Visual Studio 2008 Command Prompt as “Administrator”. Navigate to C:\Windows\Microsoft.NET\Framework\v3.0\Windows Communication Foundation. Run this command servicemodelreg –i.


In my case, along with Mekanik's suggestions, I was receiving this error in Windows Server 2012 and I had to tick "HTTP Activation" in "Add Role Services".


In windows server 2012, even after installing asp.net you might run into this issue.

Check for "Http activation" feature. This feature is present under Web services as well.

Make sure you add the above and everything should be awesome for you !!!