I’m not sure what that means. I doubt that is true. Optimus technology was introduced well before the GTX 1060 was delivered.
I think its likely that your dGPU is not enabled for some reason. That could be the reason for cudaErrorUnknown. It may also be that your OpenGL stack is broken. If you installed CUDA (including the GPU driver) without installing the NVIDIA OpenGL driver components, that would do it.
I doubt I will be able to give you a recipe to sort this out, however there are many forum posts on these topics. The CUDA installation forum is where you will find questions like this.