I'm one of 2 admins on a FB page which, all of a sudden, displays the above message ONLY when I try to edit, or pin a post, using the drop-down arrow. It DOESN'T happen on my personal timeline NOR on another page I'm admin on.
I've cleared the cached & cookies, tried multiple browsers and still get the message. Interestingly, I don't have the issue on my mobile device, and the other admin has no problems, either.
A google search for the error message produces results which...in so many words tell me, "Sh*t happens. There's no fix."
Anyone? And, as always, Thank You!
Tried 3 different browsers, all the same result. Sent a message to FB support explaining the issue and their response was, "Your feedback will be used to improve Facebook. Thanks for taking the time to make a report." Gee, thanks, FB.