ASP.NET: 401 unauthorized access is denied due to invalid credentials

Solution 1: (this will end up with @User.Identity.IsAuthenticated be empty string)

• In IIS, select the website you're having the issue with.
• In the IIS section, select 'Authentication'.
• Right click on Anonymous Authentication and select 'Edit'
• Check the 'Specified User' radio button and click on 'Set'
• I entered my username, password and password confirmation and click ok.

Fix:“401 – Unauthorized: Access is denied due to invalid credentials“ on ASP.NET MVC & IIS 7
https://support.microsoft.com/en-ca/kb/871179