I have an ASP.NET MVC 3 application with forms authentication. For some reason that I cannot see, the login redirect url is /Account/Login?ReturnUrl=%2fSecure%2fAction
I ran into a similar problem sometime ago. After a few months I discovered the root of the problem: I had added a 'deployable dependency' on 'ASP.NET Web Pages with Razor Syntax'. This adds a reference to: WebMatrix.Data.dll
This assembly has a class with a static constructor that does the following:
static FormsAuthenticationSettings()
{
FormsAuthenticationSettings.LoginUrlKey = "loginUrl";
FormsAuthenticationSettings.DefaultLoginUrl = "~/Account/Login";
}
Check if you are referencing this dll.