Simple Form Authentication doesn't seems to work in MVC4

Hi guys,
I'm just trying to get this simple form authentication working for MVC4 application but doesn't seems to work.
Can you guys help me out?

In web.config i have:
<authentication mode="Forms"> <forms loginUrl="~/Account/Login" timeout="2880"> <credentials passwordFormat="Clear"> <user name="Admin " password="password" /> </credentials> </forms> </authentication>
Then in the Http Post controller, I have
if (FormsAuthentication.Authenticate(model.UserName, model.Password))
But this doesn't seems to work anymore. Am i missing something?
I've also tried
if (Membership.ValidateUser(model.UserName, model.Password)) and played around with membership setting in web.config
but no luck :(
...