When the app may be to post for an user in the wall of your friends...
Error 201: User not visible in facebook api
Please if any people can explain me about this error, and its causes. I don't know mouch about facebook api, but I understand that a post publication by an application integrated with facebook can publish unlimited post for any user.
Why a user is not visible in facebook api???
It seems it's a bug: http://bugs.developers.facebook.net/show_bug.cgi?id=11471 Many people report this, I also encountered this problem today...
Thanks, it ocured when a facebook profile is added to system DB but the profile owner is not added the applicaon in your facebook profile and you security is blocked for unknow applications
来源：https://stackoverflow.com/questions/4703365/error-201-user-not-visible-in-facebook-api