if you just installed iis and you get this error, it’s because of windows security stuff so you need to:

1. right click on the folder containing your site files
2. click on properties
3. click on security tab
4. click on edit
5. click on add
6. click on advance
7. click on find now
8. find IIS_IUSR AND IUSR
9. then click ok
10. then click ok
11. then click ok
12. then click ok

try now and you will not see that error again