IIS 8 - Default Document - resource cannot be found

Another possible reason of the 404 error when your request doesn't point to a specific file name at the end of URL is that your IIS Request Filtering rules deny extensionless requests.

To know it for sure, figure out the subcode of the 404 error.Usually, it's 404.7, but there may be some variations,

Also, you can try to allow extensionless requests explicitly by adding <add fileExtension="." allowed="true" /> to your web.config as below:

  <system.webServer>    <security>      <requestFiltering>        <fileExtensions>          <add fileExtension="." allowed="true" />        </fileExtensions>      </requestFiltering>    </security>  </system.webServer>

Please let me kniw if it helped or post your exact 404 error with the subcode.

From your tags it looks like you use MVC and a view using the razor view engine (cshtml). In MVC an URL does not map to a document directly. So the discussion should not be about default documents, handlers and IIS configuration.

An URL must match a defined route, which invokes an action on a controller. This action will then render the view (*.cshtml).

Try to fix your routes to be able to handle the request. If you need more help, you should update your question with more information about the controller and your routes.

You can made a web Site/Application installer. it has option to set the start up page selection.

So set the ChatPage.cshtml as your start up page in installer and after installing if you type localhost/SignalIRChat

you will see the content of ChatPage.cshtml without showing the "ChatPage.cshtml" name in address bar.

It will resolve your problem.