why do I get “Invalid appsecret_proof provided in the API argument”

Question

Since the latest change on Facebook, regarding the appsecret_proof: https://developers.facebook.com/docs/reference/api/securing-graph-api/, we are still unable to download p

Answer 1

Works for me:

$appsecret_proof = hash_hmac('sha256', $facebook_page_token, $app_secret);

WHERE facebook_page_token is the page token stored in my database created when I associate the page to the app.