You are logging into Single Sign On system (SSO). After a single login, this system enables you to access multiple secured applications (e.g. portal, EPS) using an unique web browser instance.
As for Username and Password, please use the username and password from LDAP (ie. username and password used for logging reading the mail).
Please, do not add this page into Favorites list in your web browser. Otherwise you won't be able to login in future. Instead of adding this page you can add the initial page shown after login.