HTTP Error 500.19 - Internal Server Error - Error Code 0x80070005

I have created a virtual directory in IIS > MySite as /Media to a network drive. //129.1.1.44/media/.
This is opening without any issues in explorer and i have the full permission to the folder,

when i right click the media folder from iis and select explore it's opening without any issues.

i also have given Full Control permission for IUSR, ISS_IUSRS, Network_Services on this folder.

But when i right click > Manage Virtual Directory > Browse i'm getting below error.

reading file (using  Dim path As String = Server.MapPath("~/MEDIA/123456.jpg") ) is working fine for me.

but i'm not able to upload.SaveAs any file to this folder. getting error "Access to the path '\\129.1.1.44\media\xyz.pdf' is denied." 

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     0x80070005 
Config Error   Cannot read configuration file due to insufficient permissions  
Config File    \\?\UNC\mysite\media\web.config 

Requested URL  http://localhost:8080/MEDIA 
Logon Method   Not yet determined 
Logon User     Not yet determined 

Config Source:
   -1: 
    0: 

Can someone help me on this please