Originally Posted by SpinelesS
They meant your Xbox's privacy settings, not GTA V's.
From Xbox dashboard: settings/privacy/change settings/customize and see if Social Network Sharing is set to allowed
EDIT: From your Rockstar social page I checked your Facebook and twitter feeds and the game hasn't posted a single message on either, so I think there is a good chance it is your XBOX's privacy settings.
Was just about to clarify that this ^^^ was what I was talking about. As soon as I allowed Social Networking I had no problems.