Installing : Installing System Architect XT : Verifying System Architect XT website properties in IIS : 2: Setting directory security manually
  
2: Setting directory security manually
1 Click the Authentication icon.
2 Set ASP.Net Impersonation to Enabled.
3 Set Windows Authentication to Enabled.
The rest of the Authentication methods can remain Disabled.
Next
3: Setting the default page for System Architect XT website manually
See also
Verifying System Architect XT website properties in IIS