WebApi's {“message”:“an error has occurred”} on IIS7, not in IIS Express

Question

I\'m working with ASP.NET MVC 4 WebApi and am having a lot of fun with it running it on my local computer on IIS Express. I\'ve configured IIS Express to serve remote machi

Answer 1

None of the other answers worked for me.

This did: (in Startup.cs)

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        var config = new HttpConfiguration();

        WebApiConfig.Register(config);

        // Here: 
        config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;
    }
}

(or you can put it in WebApiConfig.cs):

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // Web API routes
        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{action}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

        // Here: 
        config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;
    }
}

Answer 2

I had a similar problem when posting to the WebAPI endpoint. By turning the CustomErrors=Off, i was able to see the actual error which is one of the dlls was missing.

Answer 3

If you have <deployment retail="true"/> in your .NET Framework's machine.config, you won't see detailed error messages. Make sure that setting is false, or not present.