So I’m watching a video and saving words and phrases (marking as known, learning, or not learn or saving the phrase) but when i open Language Reactor it’s not there. Why?
I am sure I checked on all the tabs of the documentation that can be found here : Language Reactor.
Thanks for your help 
Now there is an error when saving words from youtube. Netflix still does save the marked items.
Check the right tab or turn off ad blockers.
I have the exact same problem. LR is not saving words from Youtube, but it does save words in other apps. Unfortunately, I only use LR for Youtube videos. Everything was working fine until this morning. I have a one year subscription for pro version. LR has terrible customer service, basically completely non-existent.