In IIS Manager, right click on Sites, and enter the information for the site. By default, the root directory for the website will not have the permissions needed, and if we don't handle this, HTTP Error 401.3 will show when attempting to get the .HTML .PHP files. Follow these directions to resolve this.

1. Right click on the root directory folder, and select Properties
2. Click on the Security Tab
3. Click on the Edit Button
4. Click on the Add Button
5. Click on the Advanced Button
6. Click on the Find Now Button
7. Select IUSR
8. Press OK four times

Now, we should no longer get the HTTP 401.3 error.