using windows authntication not getting login prompt

<configuration><connectionStrings><add name="ActiveDirectory" connectionString="LDAP://DC1:389/DC=smstest,DC=local"/><add name="PEXConnectionString" connectionString="Data Source=.\sqlexpress;Initial Catalog=LUSD;Integrated Security=True" providerName="System.Data.SqlClient"/></connectionStrings><system.web><membership defaultProvider="ADMembershipProvider"><providers><add name="ADMembershipProvider" type="System.Web.Security.ActiveDirectoryMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"  connectionStringName="ActiveDirectory" connectionUsername="smstest\administrator" connectionPassword="****" attributeMapUsername="sAMAccountName" applicationName="PEx-SchoolTool" /></providers></membership><roleManager defaultProvider="WindowsProvider"
  enabled="true"
  cacheRolesInCookie="true"><providers><add name="WindowsProvider"
          type="System.Web.Security.WindowsTokenRoleProvider" /></providers></roleManager><authentication mode="Windows"></authentication><trust level="Full" originUrl=""/><compilation debug="true" targetFramework="4.0"/><httpRuntime/></system.web></configuration>