Cant access NVIDIA-SMI

When i run my program, it says gpu device not found.
error: (-217:Gpu API call) no CUDA-capable device is detected in function ‘ManagedPtr’

so i entered nvidia-smi and some other commands in terminal, and they all returned errors like this:
NVIDIA-SMI has failed because it couldn’t communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.

What seems to be the issue here? I have run programs before, and never got this issue.

Hi , I m having the same issue, any updates on this ?