Forms Authentication Logging Out on Transfer

Hi all,
I'm being logged out after RedirectFromLoginPage, can you see why?


Login page:
Protected Sub Login1_Authenticate(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.AuthenticateEventArgs) Handles Login1.Authenticate
        If Membership.ValidateUser(Login1.UserName, Login1.Password) Then
            FormsAuthentication.RedirectFromLoginPage(Login1.UserName, Login1 .)
        End If
    End Sub


web.config:


<authentication mode="Forms">
          <forms name="MCERTSSamples"
               loginUrl="~/Insecure/Users/Login.aspx"
       &nbs ...