Error with nvidia-debugdump


I’m trying to install 12 cards on Ubuntu server 20.04

VIDIA Corporation TU116 [GeForce GTX 1660 SUPER].

But I’m getting this error:

nvidia-debugdump --list
Found 12 NVIDIA devices
Error: nvmlDeviceGetHandleByIndex(): Not Found
FAILED to get details on GPU (0x0): Not Found

Unable to determine the device handle for GPU 0000:01:00.0: Unknown Error

What could be the cause and how to solve it?