Trying to install DNN 8.0.3 in Windows 10. I have checked file level permissions, INETMGR settings appear to be correct, get same error when trying to open site from within configuration manager. I get the following error message;

Thanks for the input, if I did it correctly I went to "Add Application" set the Alias, application pool and physical path, pass through authentication is enabled. When I "Test Settings" I get the following error message;

Authentication: Pass-through  authentication is good!

Authorization: Cannot verify access to path C:\WebSites\MyWebsite

The server is configured to use pass-through authentication with a built-in account to access the specified physical path. However, IIS Manager cannot verify whether the built-in account has access. Make sure that the application pool identity has Read access to the physical path. If this server is joined to a domain, and the application pool identity is NetworkService or LocalSystem, verify that <domain>\<computer_name>$ has Read access to the physical path. Then test these settings again.

I have added the AppPoolIdentity to the C:\WebSites\ folder and child folders and files with read and modify permissions.