I was running a deep learning program on my Linux server and I suddenly got this error.

UserWarning: CUDA initialization: Unexpected error from cudaGetDeviceCount(). Did you run some cuda functions before calling NumCudaDevices() that might have already set an error? Error 804: forward compatibility was attempted on non supported HW (Triggered internally at /opt/conda/conda-bld/pytorch_1603729096996/work/c10/cuda/CUDAFunctions.cpp:100.)

Earlier when I just created this conda environment, torch.cuda.is_available() returned true and I could use CUDA & GPU. But all of a sudden I could not use CUDA and torch.cuda.is_available()returned false. What should I do?

ps. I use GeForce RTX 3080 and cuda 11.0 + pytorch 1.7.0. It worked before but now it doesn't.