ffmpeg - Record Server Desktop Without Connection

I set up an application which uses ffmpeg to record a desktop on an Amazon AWS EC2 instance having Windows Server 2012 R2 installed. It records the desktop and puts the result into a file.

This works as long as a Remote Desktop or TeamViewer connection is active for that particular Amazon AWS EC2 instance. As soon as I close the Remote Desktop and TeamViewer connection the recording stops and continues as soon as I reconnect.

I assume that it's because the GPU doesn't deliver frames without a display in use.

How can I make sure that frames are constantly being rendered so that I can record them?