From what i can see in log file there is problems with the Cryptodome, and I also know there were changes in inputstream.adaptive in the latest leila builds. I dont know if they are related. But I would reinstall, and if it doesn’t work try a leila build prior to 205. Which i know isn’t easy for a beginner, but after you installed leila, then run this command:
sudo apt-get install rbp2-mediacenter-osmc=17.8-204
That is if you are running on a pi2/3, else on a vero4k
sudo apt-get install vero3-mediacenter-osmc=17.8-204
edit: After upgradeing to latest Leila(17.8-209) i got one sadface when starting Netflix addon, but after the automatic restart of mediacenter(sadface) the netflix addon did work.