HTTP Error 404.3 - Not Found
The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.

This problem will occur if ASP.NET is not installed correctly in your server. Please follow the steps below to rectify this issue:

  1. Navigate to C:\Windows\Microsoft.NET\Framework64\v4.0.30319
  2. Type the command aspnet_regiis -iru
    -iru - Install this version of ASP.NET. If there are any existing applications that uses ASP.NET, it will not change IIS configuration to use this version.
  3. aspnet_regiis -iru
  4. Make sure BizTalk360 application pool is configured to run .NET Framework 4.0 and Integrated mode
  5. Reset IIS

For customers using Windows Server 2012 and later, if the error is encountered in the operating system then the HTTP activation needs to be turned on in the Windows features in Server Manager by navigating to .Net Framework 4.5 Features> WCF Services> HTTP Activation.