[Solved] Adding Comments with FB

Hi, I'm really sorry if this is in the wrong section im new...

I've tried to add the login from Facebook on my blog comments and all I get is this

URL blocked: This redirect failed because the redirect URI is not white-listed in the app's client OAuth settings. Make sure that the client and web OAuth logins are on and add all your app domains as valid OAuth redirect URIs.

I followed the instructions and done everything as it says. The twitter one works but not FB
Ive tried to google that but i cant seem to find a cure

Thanks