Facebook and Instagram feeds failure may have the same reason and solution can be the same for both.
Be aware that content feeds of Facebook groups were restricted by the platform.One of the reasons why Facebook content feed stopped working is your Facebook account password change.
When you generate Facebook feeds, you need to authenticate your Facebook account. Facebook issues your personalized Facebook token during the authentication process. When you change your password in your Facebook account this token expires and your Facebook content feeds stop working.
To reactivate your Facebook feeds you need to choose the feed that's not working, go to the feed's editor, re-authenticate your Facebook account and save the feed. You don't have to re-authenticate your Facebook user for each Facebook feeds. All the feeds with the same Facebook user will be resumed automatically.
Another reason is the natural Facebook token expiration. All Facebook tokens expire every 2 months. And you need to re-authenticate your Facebook user to update your token. When your Facebook token is expired we send you an email notification, please don't ignore them.
Note: there is no need to generate new feeds in both cases! Especially if you use such feeds in posting campaigns and content widgets. The best way is to resume your existing Facebook feeds.
One more reason why your Facebook feeds stopped working is a problem with the original Facebook page. The Facebook page could be deleted, renamed, changed its URL or hidden from the public. You need to find another Facebook page with similar content and generate a new feed.
If you are sure that none of the problems listed above is the cause, most likely Facebook connection was lost. You need to go to the Facebook feed editor, press Disconnect and then Authenticate. Then save the feed.
If this doesn't help, you need to go to your Facebook account - Settings - Security and login - Apps and websites (or Business integrations). Remove RSS Ground app.
Then go to your Facebook feed and Authenticate your Facebook user over again. Save the feed.
Note: be careful when you remove RSS Ground app in your Facebook account. Since we use the same app for Facebook feeds, Instagram feeds, Facebook and Instagram Posters, in case you use them you need to re-authenticate your Facebook user there as well.