Hello @KathrynP82 ,
If you're referring to the little pale-blue message at the bottom of each post, that is simply a reminder - not an error message. Error messages will typically appear in pale-red / pink boxes, or will be a full page with a graphic and message.
With that said, it looks like you only have a single Facebook account being used. Have you tried resetting the API permissions for the connected Facebook account? With all the recent API and 3rd party access changes FB's been making recently, it causes some functionalities like ours to need a full reset of permissions. To perform this for your account:
You may also need to do this in the future for Facebook and Instagram accounts in general, because their API permission naturally expire without any actual warning or alerts.