Object moved to here. Asp.net Login Control

Question

I have an .aspx page that contains an web control.

previously it was working but from past 2 - 3 days it displays **

Object moved to here.

** error after login.

and still it is working in local host.

Code in aspx page is:

<asp:Login ID="Login1" runat="server" DestinationPageUrl="~/Backend/ControlPanel.aspx"
            OnLoggedIn="Login1_LoggedIn" Style="font-family: Arial; font-size: 12px; height: 200px;
            width: 350px; float: left;" DisplayRememberMe="false" PasswordRecoveryText="Forgot Password"
            PasswordRecoveryUrl="~/Backend/PasswordRecovery.aspx">
        </asp:Login>

Code in Aspx.cs page

protected void Login1_LoggedIn(object sender, EventArgs e)
{

    if (Membership.ValidateUser(Login1.UserName, Login1.Password))
    {
        string[] roles = Roles.GetRolesForUser(Login1.UserName);
        if (roles.Contains("Admin"))
        {
            UserManagement userMgmt = new UserManagement();
            Session["LoggedInUserName"] = Login1.UserName;
            AdminMangagementBLL.SetAdminModuleInstancePrivilegesInSession(userMgmt.GetCurrentUserNameFromSession());
        }
        else
        {
            Session["LoggedInUserName"] = Login1.UserName;
        }

    }

}

Cant figureout why this happens?

is it because of server upgrade or something?

plz help.