I remember I had to fix this issue about a year ago. And I completely forgotten how to do this. And the same problem strikes again.
The issue was with a web-site (MVC5, 4.5.1 .Net) running on IIS. And I had an issue when trying to get data from SQL Server.
The connection did not go through whatever I did.
The fix was quite simple. All I needed to do is to change the AppPool underlying user to be “NetworkService” instead of “ApplicationPoolIdentity”:
- In IIS, in list of Application Pools find the one which works with your site.
- In Advanced Settings (link on right) for that AppPool find Section Process Model and Identity setting first
- Change Identity to be NetworkService
- Restart AppPool and the web-site.
This is possibly one of the reasons that can cause the issue. There is a million of other reasons this can happen, but I have checked most of them before started semi-randomly poking about with app pools and IIS settings.