If you run into an error saying that Nvidia-settings couldn't connect to the accessibility bus, it means that the driver had failed to locate the GPU. In case that you have only one GPU in the system, make sure you have plugged it to the first x16 PCI-E slot counted from the CPU.
(nvidia-settings:17822): dbind-WARNING **: 22:26:17.089: Couldn't connect to accessibility bus: Failed to connect to socket /tmp/dbus-VKiQmhPMIS: Connection refused
ERROR: Unable to load info from any available system