Facebook Real-time Updates: (#2200) callback verification failed, code 2200

Question

I am trying to get realtime updates from facebook for my application as documented in https://developers.facebook.com/docs/reference/api/realtime/. I am struggling now when it comes back to the Subscription Verification. I have set up a callback server which accepts both GET and POST requests. I verified that the server works by making curl requests to it.

However, I stil get this error when attempting to create a subscription issuing the POSt request below

{"error":{"message":"(#2200) callback verification failed: ","type":"OAuthException","code":2200}

From what I read in the documentation and other threads, I assume that this means that the single GET request to my callback URL fails. The callback url does not get requested by neither GET nor POST requests indeed. I suppose that facebook is somehow blocked from accessing the endpoint. However, I am able to auth as a user using the auth dialog (https://developers.facebook.com/docs/reference/dialogs/oauth/) where I pass a callback url on the same server as well. The server runs http (for now).

This is the curl I am using to post the subscription. Host file has an entry to redirect dev.minggler.com to localhost =>( 127.0.0.1 dev.minggler.com)

curl -XPOST 'https://graph.facebook.com/256139341164822/subscriptions?callback_url=http%3A%2F%2Fdev.minggler.com%3A3000%2Ffacebook%2Frealtimeupdates&object=user&fields=friends&verify_token=abcd123&access_token=$MYTOKEN'

Can anybody help me out on this?

Answer 1

finally found the problem. the server wasn't reachable from outside. resolving it solved the problem