There are 2 login screens, one default and a custom.
Check whether this piece of code is in your index.html. If not, add it after the <script< dojoConfig…. </script>
<script>
if (!document.cookie || !document.cookie.match(/(^|;)originURI=/gi))
document.cookie = "originURI=/login.html";
</script>
This should redirect you to the login.html which is the custom login