Handbrake won't use nvenc

[Jim]

Recently I had to reinstall Kubuntu on this machine.  I didn't have a 
problem until I tried to use Handbrake.  It will no longer use nvenc.    
I tried it using ffmpeg using the command line. First I tred ffmpeg -i 
input.mp4 -vcodec h264 output.mp4.  That worked, but failed when I 
tried  ffmpeg -i input.mp4 -vcodec h264_nvenc output.mp4 and displayed 
the error message below. Before I had to reinstall, I was able to use 
nvenc when encoding using h264 in Handbrake.  Any idea how I can fix 
this? Thanks

[h264_nvenc @ 0x55dd91a7ae40] Cannot load libnvidia-encode.so.1
[h264_nvenc @ 0x55dd91a7ae40] The minimum required Nvidia driver for 
nvenc is 520.56.06 or newer
[vost#0:0/h264_nvenc @ 0x55dd91aae5c0] Error while opening encoder - 
maybe incorrect parameters such as bit_rate, rate, width or height.
[vf#0:0 @ 0x55dd91a913c0] Error sending frames to consumers: Operation 
not permitted
[vf#0:0 @ 0x55dd91a913c0] Task finished with error code: -1 (Operation 
not permitted)
[vf#0:0 @ 0x55dd91a913c0] Terminating thread with return code -1 
(Operation not permitted)
[vost#0:0/h264_nvenc @ 0x55dd91aae5c0] Could not open encoder before EOF
[vost#0:0/h264_nvenc @ 0x55dd91aae5c0] Task finished with error code: 
-22 (Invalid argument)
[vost#0:0/h264_nvenc @ 0x55dd91aae5c0] Terminating thread with return 
code -22 (Invalid argument)
[out#0/mp4 @ 0x55dd91c55240] Nothing was written into output file, 
because at least one of its streams received no packets.
frame=    0 fps=0.0 q=0.0 Lsize=       0KiB time=N/A bitrate=N/A speed=N/A
[aac @ 0x55dd91bfa500] Qavg: 924.945
Conversion failed!