How to authenticate to the CRM 365 (with IFD config) web API in a headless mode?

Hi all,

We are trying to use the Dynamics CRM 365 web API. Our context: we have Dynamics 365 on premise (IFD enabled), and ADFS 4.0 on premise for authentication.

I am able to get an access token following the steps on https://msdn.microsoft.com/en-us/library/gg327838.aspx. However, this requires the calling application (my C# code) to run in an interactive mode. If I run my application locally, I can see that there is a quick pop-up that takes the user that is logged into Windows, and uses that for authentication.

However, when I want to use my code in a ASP.NET application hosted on a IIS, that interactivity is not allowed by the IIS. It gives the following error:

System.InvalidOperationException: Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation.

Does anyone know the recommended way in this context to authenticate?

Thanks in advance!!

Benjamin