A warning indicates that you have a newer NVIDIA card installed that does not support the acceleration of ray-traced 3D applications. This is a feature that is no longer being developed, so it is not an important one to be concerned about.
NVIDIA GPUs that are not supported for acceleration of ray-traced 3D compositions include:
Click OK in the warning message dialog box.
Use Cinema 4D Lite (bundled with After Effects CC, and later) for working with 3D and After Effects instead of ray-traced 3D compositions.
It is possible to have a supported GPU for the acceleration of ray-traced 3D compositions and still get this error.
If your GPU is on the systems requirements list for acceleration of 3D compositions (see here), then update After Effects to the most current version.
If you have a legacy NVIDIA (non-Maxwell) card that has over 1 GB VRAM, yet is unsupported, you can choose to enable untested, unsupported GPU for CUDA acceleration of Ray-Traced 3D Renderer in Preferences > Previews > GPU Information: "Enable untested, unsupported GPU for CUDA acceleration of ray-traced 3D renderer".