Hello, unfortunately this problem started to happen to me too.
Until last week everything was working. Then I updated my RTX 2060 driver and when I click on export in Premiere it appears:
---------------------------
Voukoder
---------------------------
Unable to initialize the encoder.
This has most likely to do with an invalid combination of options.
Make sure there is at least one free NVENC session and close all other programs that make use of NVENC.
---------------------------
OK
---------------------------
Changing the Field Order to None (Progressive) it works. But the performance I had before when exporting, is no longer the same.