NvIfr - Acessing the Encoder after Create results in NVIFR_ERROR_HW_ENC_NOT_INITIALIZED

I’ve successfuly called the create method ang got an ifr handle.

But when I call NvIFRSetUpHWEncoder (or any Other method except release) I get NVIFR_ERROR_HW_ENC_NOT_INITIALIZED as result.

I cannot find anything about initializing the Encoder first… and I cannot find anything more concrete about this error.

Does anyone have an idea what could be the Problem?