Why does the Windows NT® LAN Manager (NTLM) authentication fail when I attempt to log in to IT Assistant?
Ensure that your Single Sign-On is enabled in your Internet Explorer browser. To enable Single Sign-On, launch Internet Explorer. Click Tools→ Internet Options→ Security tab. Select Trusted sites. (The IT Assistant system is covered within this security zone.) Click Custom Level. Scroll down to User Authentication and select Automatic logon with current username and password.