Adding a SQL Filetable folder as a Virtual Directory

Using IIS 7.5 .NET Framework 4. I have a web page that needs to access a SQL 2012 Filetable folder. In IIS, I set up the file table folder as a virtual directory & in the connection, I'm using my active directory account login as the account to "Connect as...". I'm able to access the FileTable folder in windows explorer by going to it's location:

\\computername\sqlexp2012\filetabledb\filetabletb_dir

In IIS, if I right click on the virtual folder, and then click Explore, it opens up a Windows Explorer instance & displays the files there (lots of PDF files).

However, if I try to access the virtual folder directly (http://localhost/virtualfoldername) by right-clicking & going to Manage Virtual Directory, or access it through a web page (http://mywebsite/vname) I get the following error.

Error Summary

HTTP Error 500.19 - Internal Server Error

The requested page cannot be accessed because the related configuration data for the page is invalid.

Detailed Error Information

Module IIS Web Core

Notification BeginRequest

Handler Not yet determined

Error Code 0x80070032

Config Error

Config File

Requested URL http://localhost:80/virtualfoldername

Physical Path \computername\sqlexp2012\FileTableDB\FileTableTb_Dir

Logon Method Not yet determined

Logon User Not yet determined

Config Source

-1: 0:

If I go in to the Virtual Directory & go to Manage Virtual Directory --> Advanced Settings, I see the physical path to the SQL Filetable folder & Physical Path credentials. My user account is set up as dbo under Security --> Users. The IIS log file is not helpful, nor is anything in the Event Viewer.

Anything I've been able to find has said that it is likely permissions related, but using my account - which I know works, as far as accessing the file share via Windows Explorer - doesn't. Any thoughts welcome.

Thanks!