[HOW-TO ALL PLATFORMS]Can I use Netflix on OSMC?(post 4)

looks like you are missing libwidevinecdm.so, have you just installed v.18. Gmc removed libwidevine from his nightlys a few days ago. You can add it yourself by using a script:

Getting libwidevine:

sudo apt-get install xz-utils
nano extract-libwidevine.sh

#!/bin/bash
wget  http://odroidxu.leeharris.me.uk/xu3/chromium-widevine-1.4.8.823-2-armv7h.pkg.tar.xz -O /tmp/chromium-widevine-1.4.8.823-2-armv7h.pkg.tar.xz           
tar xJf /tmp/chromium-widevine-1.4.8.823-2-armv7h.pkg.tar.xz usr/lib/chromium/libwidevinecdm.so --strip-components=3
chmod 755 libwidevinecdm.so
if [ ! -d "/home/osmc/.kodi/cdm/" ]; then                      
 mkdir /home/osmc/.kodi/cdm/
fi
cp -ar libwidevinecdm.so /home/osmc/.kodi/cdm/    
ln -fs /usr/lib/kodi/addons/inputstream.adaptive/libssd_wv.so /home/osmc/.kodi/cdm/libssd_wv.so

chmod +x extract-libwidevine.sh
./extract-libwidevine.sh