nopCommerce works well on VS Web server. However when I run the application on IIS 7, it stops working properly.
After I log in, the login link is still shown at the top and when I go to account.aspx, it keeps redirecting to login.aspx. The same things happens when checking out. Shopping cart is however populated after logging in!

I ran it in debug mode and noticed that HttpContext.Current.User is always null.

Administration area is working well and HttpContext.Current.User is populated for those pages.

Any idea what the problem is?