Windows NT, Windows 2000, and Windows 9x clients that try to establish a PPTP session with a Windows 2000 PPTP server receive:
Login failed: username, password, or domain was incorrect.
The account for user
The line has been disconnected.
Event ID 20189
The user tried to connect using an unauthorized dial-in media.
1. Start the Routing and Remote Access administrative tool.
2. Expand the options under your Remote Access Service (RAS) server's name.
3. Press Remote Access Policies, right-click, and press Properties on Allow access if dial-in permission is enabled.
4. Press Edit Profile.
5. On the Dial-in Constraints tab, do one of the following:
Select Restrict Dial-in Media, and then select Ethernet and VPN from the list of options available.
7. Press OK.