@andre3030, did you have netflix installed previously? Try uninstalling Netflix addon, and answer yes to remove all settings, then reinstall it.
I did a clean install, image 2018.12-1 then upgraded to Leia 18.2-rc1 and installed Netflix with one issue, libwidvine needed some missing libs, which was simply fixed, you can read about it here: [HOW-TO ALL PLATFORMS]Can I use Netflix on OSMC?(post 4) - #342 by joakim_s