Allow Users not allowing user

I created a role in the asp.net configuration tool - Admin

I created a user - John

In my project I created a folder called "Admin" with a file called "admin.aspx"

I added "admin.aspx" to my web.sitemap file

<siteMapNode url="~/Admin/admin.aspx" title="Admin" description="Admin" roles="Admin"/>

I then added a web.config to the "Admin" folder 

<?xml version="1.0"?><configuration><system.web><authorization><allow users="Admin"/><deny users="*" /></authorization></system.web></configuration>

When I log in as John I can see the link to admin.aspx but when I click on the link I get redirected to login.aspx because I don't have rights to view that page

So I checked if I was logged in as an Admin

User.IsInRole("Admin").ToString() + " " + User.Identity.IsAuthenticated.ToString()

Which returned true true.

As a test I changed the web.config in the "Admin" folder to

<allow users="User"/>

And users with the role of "User" can see the page.

I'm confused