Make sure to select your language for your post. I know it seems like it should be intuitive, but atm it is still giving people problems. Also check to see under your user settings that you have english (or whichever languages) selected you want to see/read/use. Communities with the same names do not share comments on different servers. Each one is their own entity. You can choose to participate in any or all.
I know this sounds silly, but on the top of the webpage on your plex: movies do you have it on recommended vs library? For some reason mine defaults to recommended and depending on the folder I am looking at, nothing is there. When I click on Library they magically appear.
I am by no means an expert on the platform, just sharing what I have encountered.
Good luck.