Problem statement
We are trying to login using the Facebook social connection we set up a while ago, and we are getting the following error:
Error Accessing App
We’re sorry, but the application you’re trying to use doesn’t exist or
has been disabled.
Cause
The application you created in the Facebook Developer portal is disabled for some reason. Sometimes Facebook does this for compliance or other reasons.
Solution
You need to go to the Facebook Developer portal and re-enable the app you created for the Facebook social connection.