I host an Facebook application (https://apps.facebook.com/igoaltip/) on AppFog. Suddenly it stopped working. When I try to get information about the user using user access token (https://graph.facebook.com/me), Facebook returns OAuthException (#5) Unauthorized source IP.
I use Node.JS on server with facebook-node-sdk.
I do not specify IPs in server IP whitelist.
Currently experiencing the same issues on Appfog regarding Facebook requests. AppFog might have received a block from Facebook.
We added the US east IP's of appfog to our whitelist, but for more then half an hour we still receive the same error. Stangely enough we can still use the apps tokens from other IP's. This causes me to believe it takes quite a while for Facebook to enforce the whitelist