The solution i found for this problem is on this blog post .
http://stackoverflow.com/questions/4736140/login-failed-for-user-iis-apppool-classic-net-apppool
- Go into IIS Manager
- On the node with your computer name, select "Application Pools"
- Click "Classic .NET AppPool" and select "Advanced Settings..."
- Select "Identity" property and change its value to "LocalSystem"
23b68122-de6c-4e3c-b870-4e83990057d0|0|.0|96d5b379-7e1d-4dac-a6ba-1e50db561b04
IIS
IIS APPPOOL Classic .NET AppPool