Facebook Insights API Problems

2019-03-25 update: most of the API functionality appears to be working once again.

2019-03-22 There are two problems currently affecting Facebook Insights API, one causing no results for Page Insights and one causing errors for Post Insights. Both problems have been acknowledged by the Facebook Engineering team and have been assigned, but no estimated time for a fix has been stated.

Reference: https://developers.facebook.com/support/bugs/