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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 an article I've already posted, using the drop-down arrow. It DOESN'T happen when I edit comments or on my personal timeline NOR on another page I'm admin on.
As my mouse rolls over the down arrow "link" I get the message.
I've cleared the cache & cookies, tried multiple browsers and still get the message. Interestingly, I don't have the issue on my mobile device, and the other site admin has no problems, either.
There are HUNDREDS of reports about the same issue on the FB help forums, but nary a solution to be found. Anyone?
A google search for the error message produces results which...in so many words tell me, "Sh*t happens. There's no fix."