IIS 401 Unauthorized Access Is Denied Using Anonymous Access

When using Anonymous access to host a website in IIS, you get a 401 Unauthorized: Access is Denied error. This is because you don’t have the NTFS permissions set correctly on the file / folder containing your website’s files. To fix the 401 error, check what permissions you are running anonymous as (probably the IIS_IUSR account), then add read permission for that account on the file / folder.