I use FB to keep in touch with a specific group of people internationally. A few days ago, I found I had lost the ability to read comments, write comments, “like” posts or see others’ “likes”, or admit people to the closed discussion group I’m the moderator of. I can read new posts and write new posts. I can write and receive PMs.
I have no clue why this happened or how to fix it. Any ideas at all?
It sounds like you’re not logged in.
Does the rest of FB work normally? Do you belong to other groups where you can still participate in discussions?
Are you sure you didn’t accidentally leave the group somehow?
Zuckery!
I am logged in. I logged out and logged back in to see if that made any difference. It didn’t.
I cannot see nor make any comments anywhere, in my own group or any other. I cannot comment on my own ‘home’ page either (I can post on it, like I can everywhere, I just can’t read comments.) Private messaging works.
I did not leave my own group or any other group.
Update: although there is very little on the innertubes about this, I finally got the bright idea of clearing my browser cache, and the whole thing went away.
Just in case someone has the same or similar problem.
Clearing cache does seem to solve a lot of computer problems. So does rebooting. 
Also, checking stuff out with a different browser is a good troubleshooting step.
Agree, and that was going to be step 3 (I already did the rebooting, log off/log on things).