Error message no resolution

I tried to set up my facebook feed and on the display page I got this message:

Message: Invalid “Facebook App Id” ,”Facebook Secret Key” or “Facebook Page Id”

As far as I can tell, each of these are correct.
I tried using both the full url for the page id, and just the identifier,

https://www.ads-software.com/plugins/all-in-one-social-feeds/