When your Web site is hosted on Windows 2000, and you uses Windows Integrated authentication, a user may receive Error 500: The function requested is not supported when they attempt to connect to the site.
This behavior is indicative of having a strict security template applied to the IIS server that is preventing clients from authenticating.
To resolve this behavior, use the default security template:
1. Open a CMD.EXE window and type the following command, and press Enter:
secedit /configure /cfg %SystemRoot%\repair\secsetup.inf /db secsetup.sdb /verbose
2. Using REG.EXE from the Support Tools on the operating system CD-ROM, type the following commands, pressing Enter after each command:
REG HKLM\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0 /V NTLMMinServerSec /T REG_DWORD /F /D 0
REG HKLM\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0 /V NTLMMinClientSec /T REG_DWORD /F /D 0
3. Shutdown and restart your IIS server.