What can I do when suddenly I can't post to my own Facebook group my page, an Administrator?

So I noticed this just last night: In my own group, I am unable to post from my Page. I am also unable to comment on most content in there, as well. I can't even see the post box (that says "write something").I'm able to interact as normal in other groups. I checked.If I switch to other Pages of mine within the group, or to my personal profile, those also act as normal with posting and commenting abilities.I checked - I'm still Administrator.I found a workaround to access the "post" box by adding myself as a group expert and clicking "write an informative post", and that's how I got to see the error in the attached image.If I knew a way to contact Facebook support, I would, but as it is I don't know what to do :(Any and all help is appreciated. Thank you.