FBAPIException

On the log page of the plugin dashboard, every 24 hours I receive an error message “FBAPIException Please, connect your facebook account to make operations to the custom audiences of your Ad account.” https://www.screencast.com/t/kDdjVv3Kyn
I have checked all my relevant pages with the chrome extension pixel helper and all perform OK. https://www.screencast.com/t/XSVxM6QC
In General Settings all looks OK https://media.publit.io/file/2019-05-20_1832.png
can you please point me in the right direction to solve this please.