401 Unauthorized: Access is denied due to invalid credentials

Question

I am using IIS Express to deploy MVC4 application. This website runs perfectly on same computer. But in Lan it gives me error 401.

<authentication mode="Forms">
    <forms loginUrl="~/" slidingExpiration="true" timeout="20">
    </forms>
</authentication>

In home controller

[HttpPost]
[AllowAnonymous]        
public ActionResult Index(LoginModel model, string returnUrl)
{
}

I am starting IIS server from command prompt in Administrator mode. IIS responds to the request with error 401.

Any clue?

Answer 1

I realize this is an older post but I had the same error on IIS 8.5. Hopefully this can help another experiencing the same issue (I didn't see my issue outlined in other questions with a similar title).

Everything seemed set up correctly with the Application Pool Identity, but I continued to receive the error. After much digging, there is a setting for the anonymous user to use the credentials of the application pool identity or a specific user. For whatever reason, mine was defaulted to a specific user. Altering the setting to the App Pool Identity fixed the issue for me.

1. IIS Manager → Sites → Website
2. Double click "Authentication"
3. Select Anonymous Authentication
4. From the Actions panel, select Edit
5. Select Application pool Identity and click ok

Hopefully this saves someone else some time!